Dissolved Oxygen Meter

9251M Handheld Polarographic Meter with Memory by Jenco

• Clear LCD displays dissolved oxygen as percent air saturation or as parts per thousand simultaneously with temperature.
• Convenient one point calibration for dissolved oxygen. Calibration data is stored in memory and is ready for use on power up.
• User selectable salinity and pressure compensated dissolved oxygen readings.
• Work with accurate and reliable polarographic dissolved oxygen probes.
• Inclined back provides ideal viewing angle for benchtop use.
• 50 memory storage of dissolved oxygen with temperature reading with memory location ID.
• RS-232 computer interface with software.
• IP65 waterproof.
• AC adaptor or battery power (low battery indicator).

6011M Handheld pH/ORP Meter With Batteries Only by Jenco

The Basis Portable Series is Jenco's latest iteration of our portable meters and represents a huge step forward for on-location water quality measurements. This series introduces Bluetooth or non-Bluetooth connectivity and a merging of the best features from our other series, which means we double down on reliability, usability and value.

Accurate, Reliable Measurements

• up to 3 Point calibration (pH)
• >1012 Ω input impedance (pH)
• Automatic or manual temperature compensation (pH)
• Each and every unit is hand calibrated and QC ed by at least 2 teams
• CE, RoHS complaint

Improved Usabiltiy

• Clear, large LCD
• Membrane buttons with tactile feedback On-device memory storage
• IP67 water-tight housing
• Removable, rugged protective case
• Inclined back for tabletop use

Other Meters In This Series

• Single and dual parameter pH, ORP, conductivity, TDS, salinity, dissolved oxygen,optical dissolved oxygen, pH/ORP/EC, pH/ODO
• Polarographic or optical DO
• Bluetooth and non-Bluetooth models
• With memory storage
• With or without protective case

MW600 Standard Portable Dissolved Oxygen Meter by Milwaukee

The MW600 is a compact Portable Dissolved Oxygen meter with Faster Micro Processor. This handy and ergonomically designed portable meter is ideal for anyone working on a low budget and still requires fast and reliable measurements. This portable meter measures Dissolved Oxygen with a Polarographic probe and is suitable for a wide range of applications, such as Educational and Aquaculture, as well as water and environmental analysis.

Other features include smaller, ergonomic and lighter case design, 100% larger and easier to read LCD Display, low battery warning, easy to replace screw on cap membranes and long battery life.

Rugged Carrying Case (Optional) provides handy on-site meter calibration and measurements.

MW600 is supplied complete with a MA840 D.O. polarographic probe with 3 m cable, calibration screwdriver, 2 spare membranes, MA9071s (30 mL) electrolyte solution, battery and instructions.

The MW600 calibrates easily in 2 points (at 100% saturated air and in 0 Oxygen solution) and has Automatic Temperature Compensation which guarantees the highest accuracy.

DO8500 Portable Optical Dissolved Oxygen Meter by Apera

Introducing the first Optical Dissolved Oxygen Test Kit that won't break the bank.

State of the art Luminescent Optical DO Sensor

• No Membrane, No Solution, No Hassle.
• Quick & Accurate Measurements
• The probe does not consume oxygen. No limit on water flowing speed.
• Maintenance-free. No need to calibrate before every use.
• The service life of the luminescent cap is over 8000 hours. No need to replace the cap every year.
• The special coating on the luminescent cap makes it anti-interference and unaffected by light and chemicals.
• A calibration cap comes with the probe, which allows it to be calibrated and stored in saturated air.

Intelligent Instrumentation

• Auto Salinity Compensation; Auto Temperature Compensation; Auto Air Pressure (barometric) Compensation
• Large backlit LCD screen, simultaneously displaying dissolved oxygen reading and temperature. Easy switch from mg/L and % to ppm and %.
• GLP data management: 500 sets of data storage; USB output and power supply.
• Advanced digital processing technology, supporting stable reading and auto-lock display modes.
• IP67 Waterproof dust-proof rating allows the meter to be used in harsh environments.
• Foldable stand allows use as a benchtop meter.
• Comes with a rugged carrying case, which includes a meter, an optical DO probe, and the accessories.

WD-53024-53 Dissolved Oxygen Meter Zero Oxygen Sachets, 10/PK by Oakton

Replace electrodes when they break, no longer hold calibration, cannot be rehydrated, or are not compatible with your sample.

AQ600 Standard Portable Dissolved Oxygen Meter Kit by Milwaukee

The AQ600 is a Portable Dissolved Oxygen meter ideal for use in school laboratories. Dissolved Oxygen measurements are also very important in fish farms and ponds, where Oxygen levels are continuously monitored to obtain optimal reproduction.

The AQ600 calibrates easily in 2 points (at 100% saturated air and in 0 Oxygen solution) and has Automatic Temperature Compensation which guarantees the highest accuracy. The low battery warning, easy to replace screw on cap membranes make this meter very simple to operate.

AQ600 is supplied complete with a MA840 D.O. polarographic probe with 3 m cable, calibration screwdriver, 2 spare membranes, MA7040 (20 mL) electrolyte solution, battery and instructions.

Includes

• MW600 DO Meter
• Membrane Electrolyte Refill Solution 230ml bottle
• 5 Extra Membranes
• Protective Case
• 9 Volt Battery & Testing Manual

WD-35640-60 DO 100 Portable Dissolved Oxygen Meter Kit by Oakton

No meter warm-up or polarization required so you can take dissolved oxygen measurements right away

The OAKTON DO 110 meter ensures high accuracy with independent 100% and zero adjustment calibrations, and offset adjustment capabilities. It stores and recalls 100 dissolved oxygen readings with corresponding temperature- great for field readings. This meter even displays electrode diagnostics to help determine when you need to service or replace the probe. The front keypad is water resistant. Includes a dissolved oxygen/ temperature probe, electrolyte solution, and batteries.

• Includes 30-mL of electrolyte solution, two replacement membrane caps, rinse bottle, and hard side carrying case
• Low maintenance dissolved oxygen probe comes with 10 or 25 ft. length cable
• Key in salinity and pressure manually; meter automatically calculates offset values
• Dual display shows mg/L (ppm) or % saturation plus temperature
• Hold function; Auto-off; Ready indicator

WD-35441-02 DO 600 Portable Waterproof Dissolved Oxygen Meter by Oakton

Fast dissolved oxygen measurement with automatic pressure compensation

• Includes batteries
• Durable waterproof and dustproof design with IP67 rating Even with no probes attached
• Single or multipoint calibration Fast, trouble-free calibration in air
• Large backlit graphic display Multiline display with electrode status indicator, calibration data, and more
• User-settable calibration due alarm Out-of-date or unperformed calibrations are now a thing of the past!
• Built-in real-time clock Time-and-date stamping meets Good Laboratory Practice (GLP) standards
• Advanced data management Store up to 500 data sets and download via IrDA wireless interface
• Set point alarms Audible warning when readings are outside set points limit
• No meter warm-up required Galvanic probe design lets you take measurements immediately without the typical 15-minute wait!
• Password protection Security for calibration and setup menus
• Rugged rubber boot Protects meter when out in the field

DO850 Portable Luminescent Optical Dissolved Oxygen Meter by Apera

Introducing the first Optical Dissolved Oxygen Test Kit that won't break the bank.

State of the art Luminescent Optical DO Sensor

• No Membrane, No Solution, No Hassle.
• Quick & Accurate Measurements
• The probe does not consume oxygen. No limit on water flowing speed.
• Maintenance-free. No need to calibrate before every use.
• The service life of the luminescent cap is over 8000 hours. No need to replace the cap every year.
• The special coating on the luminescent cap makes it anti-interference and unaffected by light and chemicals.
• A calibration cap comes with the probe, which allows it to be calibrated and stored in saturated air.

Intelligent Instrumentation

• Auto Temperature Compensation; Auto Air Pressure (barometric) Compensation; Manual Salinity Compensation
• Large backlit LCD screen, simultaneously displaying dissolved oxygen reading and temperature. Easy switch from mg/L and % to ppm and %.
• Advanced digital processing technology, supporting stable reading and auto-lock display modes.
• IP67 Waterproof dust-proof rating allows the meter to be used in harsh environments.
• Foldable stand allows use as a benchtop meter.
• Comes with a rugged carrying case, which includes a meter, an optical DO probe, and the accessories.

WD-35434-00 PCD 650 Portable Waterproof pH / Conductivity / Dissolved Oxygen Meter with Probes by Oakton

Simultaneously measure and display pH, Conductivity and Dissolved Oxygen

These top-of the-line waterproof meters offer features that are typically found on much more expensive models. The IP67-rated housing allows use in dirty and wet environments without harm to the meter. Datalog up to 500 points either automatically, manually, or at timed intervals. User-selectable calibration due alarms, automatic or manual standards recognition, and single or multiple calibration points provide flexibility in meeting your data quality objectives. Infrared (IrDA) wireless technology lets you easily download data no need for additional cords. The large backlit LCD shows the measured value, measured units, temperature, time, battery life, and menu options.

As always, our waterproof meters are IP67-rated for both dust and water intrusion. Even with no probes attached!

• Expanded range, resolution, and accuracy, plus increased memory and advanced communications!
• Ideal for use in dirty and wet environments

WD-35434-02 PCD 650 Portable Waterproof pH / Conductivity / Dissolved Oxygen Meter by Oakton

Simultaneously measure and display pH, Conductivity and Dissolved Oxygen

These top-of the-line waterproof meters offer features that are typically found on much more expensive models. The IP67-rated housing allows use in dirty and wet environments without harm to the meter. Datalog up to 500 points either automatically, manually, or at timed intervals. User-selectable calibration due alarms, automatic or manual standards recognition, and single or multiple calibration points provide flexibility in meeting your data quality objectives. Infrared (IrDA) wireless technology lets you easily download data no need for additional cords. The large backlit LCD shows the measured value, measured units, temperature, time, battery life, and menu options.

As always, our waterproof meters are IP67-rated for both dust and water intrusion. Even with no probes attached!

• Expanded range, resolution, and accuracy, plus increased memory and advanced communications!
• Ideal for use in dirty and wet environments

WD-35434-70 PCD 650 Portable Waterproof pH / Conductivity / Dissolved Oxygen Meter with Kit by Oakton

Simultaneously measure and display pH, Conductivity and Dissolved Oxygen

These top-of the-line waterproof meters offer features that are typically found on much more expensive models. The IP67-rated housing allows use in dirty and wet environments without harm to the meter. Datalog up to 500 points either automatically, manually, or at timed intervals. User-selectable calibration due alarms, automatic or manual standards recognition, and single or multiple calibration points provide flexibility in meeting your data quality objectives. Infrared (IrDA) wireless technology lets you easily download data no need for additional cords. The large backlit LCD shows the measured value, measured units, temperature, time, battery life, and menu options.

As always, our waterproof meters are IP67-rated for both dust and water intrusion. Even with no probes attached!

• Expanded range, resolution, and accuracy, plus increased memory and advanced communications!
• Ideal for use in dirty and wet environments

WD-35441-00 DO 600 Portable Waterproof Dissolved Oxygen Meter with Probe by Oakton

Fast dissolved oxygen measurement with automatic pressure compensation

• Includes probe with 10-ft cable, electrolyte solution, replacement membrane caps, and batteries
• Durable waterproof and dustproof design with IP67 rating Even with no probes attached
• Single or multipoint calibration Fast, trouble-free calibration in air
• Large backlit graphic display Multiline display with electrode status indicator, calibration data, and more
• User-settable calibration due alarm Out-of-date or unperformed calibrations are now a thing of the past!
• Built-in real-time clock Time-and-date stamping meets Good Laboratory Practice (GLP) standards
• Advanced data management Store up to 500 data sets and download via IrDA wireless interface
• Set point alarms Audible warning when readings are outside set points limit
• No meter warm-up required Galvanic probe design lets you take measurements immediately without the typical 15-minute wait!
• Password protection Security for calibration and setup menus
• Rugged rubber boot Protects meter when out in the field

WD-35441-70 DO 600 Portable Waterproof Dissolved Oxygen Meter with Kit by Oakton

Fast dissolved oxygen measurement with automatic pressure compensation

• Includes probe with 10-ft cable, electrolyte solution, rubber boot, replacement membrane caps, hard carrying case, and batteries
• Durable waterproof and dustproof design with IP67 rating Even with no probes attached
• Single or multipoint calibration Fast, trouble-free calibration in air
• Large backlit graphic display Multiline display with electrode status indicator, calibration data, and more
• User-settable calibration due alarm Out-of-date or unperformed calibrations are now a thing of the past!
• Built-in real-time clock Time-and-date stamping meets Good Laboratory Practice (GLP) standards
• Advanced data management Store up to 500 data sets and download via IrDA wireless interface
• Set point alarms Audible warning when readings are outside set points limit
• No meter warm-up required Galvanic probe design lets you take measurements immediately without the typical 15-minute wait!
• Password protection Security for calibration and setup menus
• Rugged rubber boot Protects meter when out in the field

WD-35433-00 CD 650 Portable Waterproof Conductivity / Dissolved Oxygen Meter with Probes by Oakton

Great for salt water testing!

• Includes meter, conductivity cell, DO probe, and batteries
• Durable waterproof and dustproof design with IP67 rating Even with no probes attached
• Push-button calibration for all parameters 5 points for conductivity; 3 points for DO
• Large backlit graphic display Multiline display with electrode status indicator, calibration data, and more
• User-settable calibration due alarm Out-of-date or unperformed calibrations are now things of the past!
• Built-in real-time clock Time-and-date stamping meets Good Laboratory Practice (GLP) standards
• Store up to 500 data sets Infrared IrDA wireless technology makes PC downloading convenient and easy
• Set point alarms Audible warning when readings are outside set points limit
• Research-grade accuracy Resolution to 0.001 pH and accuracy to ±0.002 pH
• Electrode status indicator Calibration data provides electrode diagnostic tool
• Password protection Security for calibration and setup menus
• Rugged rubber boot Protects meter from impact (optional; included with kit)

WD-35433-02 CD 650 Portable Waterproof Conductivity / Dissolved Oxygen Meter by Oakton

Great for salt water testing!

• Includes meter and batteries
• Durable waterproof and dustproof design with IP67 rating Even with no probes attached
• Push-button calibration for all parameters 5 points for conductivity; 3 points for DO
• Large backlit graphic display Multiline display with electrode status indicator, calibration data, and more
• User-settable calibration due alarm Out-of-date or unperformed calibrations are now things of the past!
• Built-in real-time clock Time-and-date stamping meets Good Laboratory Practice (GLP) standards
• Store up to 500 data sets Infrared IrDA wireless technology makes PC downloading convenient and easy
• Set point alarms Audible warning when readings are outside set points limit
• Research-grade accuracy Resolution to 0.001 pH and accuracy to ±0.002 pH
• Electrode status indicator Calibration data provides electrode diagnostic tool
• Password protection Security for calibration and setup menus
• Rugged rubber boot Protects meter from impact (optional; included with kit)

WD-35433-70 CD 650 Portable Waterproof Conductivity / Dissolved Oxygen Meter with Kit by Oakton

Great for salt water testing!

• Includes meter, conductivity cell, DO probe, calibration standards, rubber boot, multiprobe holder, batteries, and hard carrying case
• Durable waterproof and dustproof design with IP67 rating Even with no probes attached
• Push-button calibration for all parameters 5 points for conductivity; 3 points for DO
• Large backlit graphic display Multiline display with electrode status indicator, calibration data, and more
• User-settable calibration due alarm Out-of-date or unperformed calibrations are now things of the past!
• Built-in real-time clock Time-and-date stamping meets Good Laboratory Practice (GLP) standards
• Store up to 500 data sets Infrared IrDA wireless technology makes PC downloading convenient and easy
• Set point alarms Audible warning when readings are outside set points limit
• Research-grade accuracy Resolution to 0.001 pH and accuracy to ±0.002 pH
• Electrode status indicator Calibration data provides electrode diagnostic tool
• Password protection Security for calibration and setup menus
• Rugged rubber boot Protects meter from impact (optional; included with kit)

9173 Large LCD Polarographic Dissolved Oxygen Benchtop Meter by Jenco

Dissolved Oxygen benchtop meter with extra large LCD display for ease of use. The meter uses polarographic type sensor with replaceable membranes and programmable pressure compensation, 600 to 1000 mBar and salinity compensation, 0 to 40.0 ppt. Communications is via. Features dual LCD displays for D.O. and temperature. ATC is a 10k thermistor. Power is 115/230V AC or by battery.

• Clear, large LCD display (4 1/8 x 3 1/16 in.).
• Clear LCD displays D.O. as percent air saturation or D.O. as parts per thousand, simultaneously with temperature.
• Manual or automatic temperature compensated (ATC) D.O. readings.
• User selectable salinity and pressure compensated D.O. readings.
• Works with accurate and reliable polarographic D.O. probes.
• Convenient one point calibration for D.O. calibration data is stored in memory and is ready for use on power up.
• Automatic lock mode and end point sensing are available to lock in stable readings.
• Intuitive operation with membrane keypad with tactile and audio feedback.
• Splash resistant case is made with durable, reinforced plastic for added protection. protective covers for connectors are included.
• Large LCD is offset for improved protection against unintentional damage.
• Smaller case does not clutter valuable desk space.
• 8pin DIN connector for D.O. and thermistor.
• AC adaptor or battery power.

MW605 DO - Dissolved Oxygen Portable Meter by Milwaukee

The Milwaukee MW605 MAX Galvanic Portable Waterproof Dissolved Oxygen meter is one of Milwaukee's most popular meters with its reliable and fast operation as well as its accuracy.

The Milwaukee MW605 MAX DO Meter is preferred by people looking for lab level accuracy without the cost. The Milwaukee DO Meter is popular with everyone from field biologists, educators, fish farmers, koi pond owners, water treatement plants and labs.

DESIGN FEATURES

• Fast, easy-to-read results with large digital LCD readout.
• Galvanic probe means no conditioning time.
• Repeatable, accuracy to ±1.5% of reading.
• Water Proof IP 67 Rated.
• Lightweight and portable.
• Simple 1 or 2 % saturation calibration points at 100% (water saturated air) and 0% (zero oxygen solution).
• Dedicated GLP key to store and recall data on system status.
• Available log space for up to 1000 records.
• Logged data export via USB cable.
• Altitude and Salinity compensation.
• Automatic temperature compensation °F & °C.
• Uses MA860 (included) reinforced Galvanic probe with an oxygen-permeable polytetrafluroethylene (PTFE) membrane sensor.
• 2 O-rings, membranes and one protective cap included.
• 10 feet probe cable for extra flexibility when testing.
• 3 x 1.5 volt akaline AA battery (battery included) aprox. 200 hours of battery life with continuous use with low battery warning.

PROBE MAINTENANCE

THE SILVER CATHODE SHOULD ALWAYS BE BRIGHT AND UNTARNISHED. IF IT IS TARNISHED OR STAINED, THE CATHODE SHOULD BE CLEANED GENTLY WITHA LINT-FREE CLOTH.

• Rinse the probe with deionized or distilled water.
• Replace the membrane cap using fresh electrolyte.
• Recalibrate meter.

SENSING BULB

The glass bulb loses sensitivity with use and will eventually fail. This is true of all pH probes.

Membrane Maintenance:

• For accurate and stable measurements, perfect condition of the membrane surface is needed. Protect the thin membrane from scratches, abrasion or contact with solids.
• If no measurements are taken for a few hours, protect the membrane with the plastic protective cap.
• If fouled, rinse it carefully with distilled or deionized water. If damaged, replace the membrane cap.

Note: Change the membrane every 8 weeks or more frequently if used in a specially fouling environment. Check and replace the electrolyte fill solution every 4 weeks.

STORAGE

After taking measurements, switch the meter off and clean the probe before storage. When not in use the probe should be stored with the plastic cap on.

For short term storage, the probe can also be stored in a beaker of deionized water with the protective plastic cap removed.

For long term storage, the probe should be stored dry:
1. Disconnet the probe from the meter.
2. Unscrew the membrane cap.
3. Remove any electrolyte solution from the cap.
4. Rinse the probe anode/cathode assembly with distilleed water and blot dry.
5. Screw the membrane cap onto the probe until the membrane cap is hand tight.

WD-35441-01 DO 600 Portable Waterproof Dissolved Oxygen Meter with Probe, with NIST Traceable Certificate of Calibration by Oakton

Fast dissolved oxygen measurement with automatic pressure compensation

• Includes probe with 10-ft cable, electrolyte solution, replacement membrane caps, and batteries
• Durable waterproof and dustproof design with IP67 rating Even with no probes attached
• Single or multipoint calibration Fast, trouble-free calibration in air
• Large backlit graphic display Multiline display with electrode status indicator, calibration data, and more
• User-settable calibration due alarm Out-of-date or unperformed calibrations are now a thing of the past!
• Built-in real-time clock Time-and-date stamping meets Good Laboratory Practice (GLP) standards
• Advanced data management Store up to 500 data sets and download via IrDA wireless interface
• Set point alarms Audible warning when readings are outside set points limit
• No meter warm-up required Galvanic probe design lets you take measurements immediately without the typical 15-minute wait!
• Password protection Security for calibration and setup menus
• Rugged rubber boot Protects meter when out in the field

WD-35441-71 DO 600 Portable Waterproof Dissolved Oxygen Meter with Kit, with NIST Traceable Certificate of Calibration by Oakton

Fast dissolved oxygen measurement with automatic pressure compensation

• Includes probe with 10-ft cable, electrolyte solution, rubber boot, replacement membrane caps, hard carrying case, and batteries
• Durable waterproof and dustproof design with IP67 rating Even with no probes attached
• Single or multipoint calibration Fast, trouble-free calibration in air
• Large backlit graphic display Multiline display with electrode status indicator, calibration data, and more
• User-settable calibration due alarm Out-of-date or unperformed calibrations are now a thing of the past!
• Built-in real-time clock Time-and-date stamping meets Good Laboratory Practice (GLP) standards
• Advanced data management Store up to 500 data sets and download via IrDA wireless interface
• Set point alarms Audible warning when readings are outside set points limit
• No meter warm-up required Galvanic probe design lets you take measurements immediately without the typical 15-minute wait!
• Password protection Security for calibration and setup menus
• Rugged rubber boot Protects meter when out in the field

WD-35434-03 PCD 650 Portable Waterproof pH / Conductivity / Dissolved Oxygen Meter, with NIST Traceable Certificate of Calibration by Oakton

Simultaneously measure and display pH, Conductivity and Dissolved Oxygen

These top-of the-line waterproof meters offer features that are typically found on much more expensive models. The IP67-rated housing allows use in dirty and wet environments without harm to the meter. Datalog up to 500 points either automatically, manually, or at timed intervals. User-selectable calibration due alarms, automatic or manual standards recognition, and single or multiple calibration points provide flexibility in meeting your data quality objectives. Infrared (IrDA) wireless technology lets you easily download data no need for additional cords. The large backlit LCD shows the measured value, measured units, temperature, time, battery life, and menu options.

As always, our waterproof meters are IP67-rated for both dust and water intrusion. Even with no probes attached!

• Expanded range, resolution, and accuracy, plus increased memory and advanced communications!
• Ideal for use in dirty and wet environments

WD-35643-12 DO 6+ Dissolved Oxygen Meter with Probe, 0.0 to 50.0°C Tempature Range and 0.0 to 50.0 ppt, 0 to 20 mg/L Dissolved Oxygen Range by Oakton

High accuracy combined with economical pricing

These meters provide a great value. The ranges work to test water quality in wastewater, surface water, ground water, or drinking water. A clear LCD display shows results in ppm or mg/L with enunciators to aid in use and troubleshooting. Six simple buttons allow for freezing readings, toggling between display units and temperature results, setup, calibration, and automatic barometric and salinity compensation after manual parameter inputs. Additional benefits of the simple design allow you to view electrode slope, zero offset, and millivolt values for electrode diagnostics.

• Includes Galvanic dissolved oxygen probe, electrolyte solution, membrane caps,protective rubber boot, and batteries
• Low-maintenance, Galvanic probe requires no warm-up time

WD-35643-14 DO 6+ Dissolved Oxygen Meter Kit, 0.0 to 50.0°C Tempature Range and 0.0 to 50.0 ppt, 0 to 20 mg/L Dissolved Oxygen Range by Oakton

High accuracy combined with economical pricing

These meters provide a great value. The ranges work to test water quality in wastewater, surface water, ground water, or drinking water. A clear LCD display shows results in ppm or mg/L with enunciators to aid in use and troubleshooting. Six simple buttons allow for freezing readings, toggling between display units and temperature results, setup, calibration, and automatic barometric and salinity compensation after manual parameter inputs. Additional benefits of the simple design allow you to view electrode slope, zero offset, and millivolt values for electrode diagnostics.

• Includes galvanic DO probe, membrane caps, electrolyte solution, sample bottles, protective rubber boot/stand, batteries,and hard plastic carrying case
• Low-maintenance, Galvanic probe requires no warm-up time