Transmit readings conveniently via Bluetooth

testo saline pots for control and humidity adjustment of humidity probes, 11.3 %RH and 75.3 %RH with adapter for humidity probe.

For the detection of carbon monoxide in indoor areas: use the high-precision CO probe (with the appropriate measuring instrument) to measure the CO concentration. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient.

For the detection of carbon monoxide in indoor areas: use the high-precision CO probe (with the appropriate measuring instrument) to measure the CO concentration.

For assessing indoor air quality: use the probe (with the compatible measuring instrument) to measure CO₂ concentration, humidity and air temperature. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient.

For assessing indoor air quality: use the probe (with the compatible measuring instrument) to measure CO₂ concentration, humidity and air temperature.

For measurements in cleanrooms and laboratories, and critical processes in the pharmaceutical, industrial and food sectors, as well as in storage, refrigerated and work rooms or in air conditioning/ventilation ducts: use the high-precision humidity/temperature probe (with the compatible measuring instrument) to measure relative humidity and air temperature. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient.

For measurements in cleanrooms and laboratories, and critical processes in the pharmaceutical, industrial and food sectors, as well as in storage, refrigerated and work rooms or in air conditioning/ventilation ducts: use the high-precision humidity/temperature probe (with the compatible measuring instrument) to measure relative humidity and air temperature.<br />&nbsp;

Ideal for air outlets in cleanrooms: use the high-precision vane probe (with the compatible measuring instrument) to measure even the lowest air velocities and volume flows as well as the temperature. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient.

Ideal for air outlets in cleanrooms: use the high-precision vane probe (with the compatible measuring instrument) to measure even the lowest air velocities and volume flows as well as the temperature.

For measurements in ventilation ducts: use the hot wire probe (with the compatible measuring instrument) to measure air velocity, volume flow, air temperature and humidity. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient.

For measurements in ventilation ducts: use the hot wire probe (with the compatible measuring instrument) to measure air velocity, volume flow, air temperature and humidity.

For measurements in storage, refrigeration and work rooms, in ventilation ducts and also on refrigeration systems and heat pumps: use the humidity/temperature probe (with the compatible measuring instrument) to measure relative humidity and air temperature. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient.

For measurements in storage, refrigeration and work rooms, in ventilation ducts and also on refrigeration systems and heat pumps: use the humidity/temperature probe (with the compatible measuring instrument) to measure relative humidity and air temperature.

Bluetooth handle for measurements without any bothersome cables: the readings are transmitted directly to your measuring instrument via Bluetooth. Combine the handle with different probe heads (please order separately) to easily expand your portfolio of probes.

Use the cable handle if Bluetooth<sup>&reg;</sup> signals are not permitted: the readings are transmitted to the compatible measuring instrument via the fixed cable. Combine the handle with different probe heads (please order separately) to easily expand your portfolio of probes.

Use the vane probe to determine air velocity, volume flow and temperature at air outlets, as well as at plate outlets, ventilation grilles or swirl outlets. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient.

Use the vane probe to determine air velocity, volume flow and temperature at air outlets, as well as at plate outlets, ventilation grilles or swirl outlets.

For measurements in ventilation ducts: use the vane probe (with the compatible measuring instrument) to measure air velocity, volume flow and air temperature. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient.

For measurements in ventilation ducts: use the vane probe (with the compatible measuring instrument) to measure air velocity, volume flow and air temperature.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>Ideal for Testing, Adjusting and Balancing (TAB) / (Retro)-Commissioning &ndash; Professionals (BSC / RCx) or Cleanroom Performance Tester (CPT) the testo 400 Air Flow kit meets highest standards when it comes down to accuracy and durability for air velocity measurements on HVAC systems.
<h3>&nbsp;</h3>

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>Ideal for Commissioning and IAQ investigation professionals

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>The testo 400 IAQ Kit is ideal for Commissioning and IAQ investigation professionals verifying building HVAC system performance parameters.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>This testo 440 kit is great for carrying out measurements at air outlets. The testo&nbsp;440 air velocity and IAQ measuring instrument and its vane probe (&Oslash; 3.9&quot;) with temperature sensor can all be safely stored in the included case.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>This testo 440 kit is great for carrying out measurements in ventilation ducts and at air outlets. The testo&nbsp;440 air velocity and IAQ measuring instrument, its vane probe (&Oslash;&nbsp;3.9&quot;) with Bluetooth and temperature sensor, and hot wire probe including temperature sensor&nbsp;can all be safely stored in the included case.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>This testo 440 kit is great for carrying out measurements in ventilation ducts and at air outlets. The testo&nbsp;440 air velocity and IAQ measuring instrument and its vane probes can all be safely stored in the included case.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>This testo 440 kit is great for carrying out measurements in storage, refrigeration, and work rooms, in ventilation ducts, and also on refrigeration systems and heat pumps. The testo&nbsp;440 air velocity and IAQ measuring instrument and its humidity/temperature probe (&Oslash; 0.47&quot;) with temperature sensor can all be safely stored in the included case.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>This testo 440 kit is great for carrying out indoor air quality measurements. The testo&nbsp;440 air velocity and IAQ measuring instrument and its CO<sub>2</sub> probe with humidity/temperature sensor can all be safely stored in the included case.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>This testo 440 kit is great for evaluating indoor air quality and determining draft risk and degree of turbulence in workplaces. The testo&nbsp;440 air velocity and IAQ measuring instrument&nbsp;and its CO<sub>2</sub>&nbsp;probe with humidity/temperature sensor and turbulence probe can all be safely stored in the included case.

Precise, reliable measurement of all air velocity and IAQ parameters with just one measuring instrument&nbsp;&ndash; the testo 440. This multifunction measuring instrument is intuitive and easy to use, thanks to its clearly structured measurement menus. Adjusting air conditioning and ventilation systems, monitoring air quality, and carrying out comfort level measurements are all possible without the hassle of juggling different devices and tools. Enjoy the versatility of using your choice of high quality digital probes with just one measuring instrument.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>This testo 440 kit is great for carrying out measurements in ventilation ducts. The testo&nbsp;440 air velocity and IAQ measuring instrument and its vane probe (&Oslash; 0.63&quot;) can all be safely stored in the included case.

<div style="margin-left:-1rem; margin-right:-1rem"><strong>When you register your product, we will extend the regular manufacturer&#39;s warranty by one year. &gt;&gt; Register now and get a warranty extension.</strong></div>
This testo 440 kit is great for carrying out measurements in ventilation ducts. The testo&nbsp;440 air velocity and IAQ measuring instrument and its hot wire probe (&Oslash; 0.35&quot;) with temperature sensor can all be safely stored in the included case.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>Carry out measurements without any annoying cables: use the kit to handle all relevant measurements in ventilation ducts and at air/ceiling outlets. You will receive the testo 440 dP air velocity and IAQ measuring instrument including differential pressure sensor and the 100 mm vane probe head and hot wire probe head (&Oslash; 9 mm) for attachment to the universal Bluetooth handle supplied.&nbsp; To make measurements more convenient, both probe heads can be combined with the telescope included in the kit. The equipment can be transported safely and conveniently in the robust case.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>Carry out measurements without any annoying cables: use the kit to handle all relevant measurements in ventilation ducts and at air/ceiling outlets. You will receive the testo 440 dP air velocity and IAQ measuring instrument including differential pressure sensor, two vane probe heads (&Oslash; 100 mm and &Oslash; 16 mm) and a humidity/temperature probe head &ndash; all three can be attached to the universal Bluetooth&lt;sup&gt;&amp;reg;&lt;/sup&gt; handle supplied. To make measurements more convenient, both vane probe heads can be combined with the telescope included in the kit. The equipment can be transported safely and conveniently in the robust case.

Precise, reliable measurement of all air velocity and IAQ parameters with just one measuring instrument &ndash; the testo 440 dP.&nbsp;This multifunction measuring instrument is intuitive and easy to use, thanks to its integrated differential pressure sensor and clearly structured measurement menus. Adjusting air conditioning and ventilation systems, monitoring air quality, and carrying out comfort level measurements are all possible without the hassle of juggling different devices and tools. Enjoy the versatility of using your choice of high quality digital probes with just one measuring instrument.

The testo 400 is the universal measuring instrument for all TAB / Commissioning and IAQ professionals. Measure, analyze and document Air flow, air pressure,&nbsp; IAQ and comfort level parameters using just one instrument &ndash; simply, conveniently and in compliance with the standards. High-quality measuring technology, intuitive measurement assistants, versatile documentation options and a comprehensive selection of air flow, comfort and IAQ probes make the testo 400 the perfect partner for your day-to-day work.

<div style="background-color: #f4f3f1;border: 1px solid #e8e6e3;border-top-left-radius: 16px;border-top-right-radius: 16px;padding: 1rem;margin: 0 -1rem 1.5rem;"><b>When you register your product, we will extend the regular manufacturer's warranty by one year. <a href="https://www.testo.com/en-US/services/product-registration-climate">&gt;&gt; Register now and get a warranty extension.</a></b></div>Ideal kit for IAQ professionals, with a focus on indoor air quality and comfort level. You will receive the testo 400 universal IAQ measuring instrument with intuitive measurement menus, one CO₂ probe (with Bluetooth<sup>&reg;</sup> handle), one turbulence probe and one globe thermometer Ø 150 mm (both with fixed cable). Use the measuring tripod to ensure standard-compliant positioning of the probes. In combination with the IAQ data logger, which is available to order separately, long-term measurements up to 2 weeks can be recorded, even without the IAQ measuring instrument.

Proven quality from Testo: you can depend on reliable measurement results, because the probe head is equipped with our long-term stable humidity sensor. This is traceable to international humidity standards, such as ILAC, PTB and NIST.<br />&nbsp;

More applications, less equipment: if you already own one of our probes with a universal handle, you can easily expand your portfolio of probes with the humidity/temperature probe head.

Temperature - NTC	Measuring range -4° to 158 °F / -20 to +70 °C
	Accuracy ±0.9 °F / ±0.5 °C
	Resolution 0.1 °F / 0.1 °C

Humidity - Capacitive	Measuring range 0 to 100 %rH
	Accuracy long-term stability: ±1 %RH / year ±0.03 %rF/K (k=1) ±2 %rH (5 to 90 %rH)
	Resolution 0.1 %rH

General technical data	Storage temperature -4° to 158 °F / -20 to +70 °C
	Weight 1.1 oz. / 30 g
	Dimensions 6.3 x 1.1 x 1.1 in. / 160 x 28 x 28 mm
	Operating temperature -4° to 158 °F / -20 to +70 °C
	Diameter probe shaft 0.472 in. / 12 mm
	Length probe shaft 5.512 in. / 140 mm
	Product colour Black

Humidity/temperature probe head

Humidity/temperature probe head

Temperature - NTC

Temperature - NTC

Humidity - Capacitive

Humidity - Capacitive

General technical data

General technical data

Accessories