Mass Flow Controllers & Meters


Whisper™ MWB–Series: Portable Low Pressure Drop Gas Mass Flow Meters

Alicat Whisper™ MWB-Series Portable Low Pressure Drop Gas Mass Flow Meters are excellent instruments for on-the-go calibration, verification, and validation. With pressure drops as low as 0.07 PSID, these portable units are a great way to minimize system impact and measure flows at near-atmospheric pressures or when there is little available system pressure.

  • Portable & durable. These meters are made to be carried around, with a battery lifetime of up to 18 hours and the ability to withstand drops.
  • Minimal system impact. Measure gas mass and volumetric flows with pressure drops as low as 0.07 PSID.
  • High-accuracy. Get real-time measurements with NIST-traceable accuracy to ±0.6% of reading or ±0.1% of full scale for 98+ gases, including custom mixtures defined using Alicat’s COMPOSER™ firmware.
  • Fast, multivariate data. Immediately upon powering up, the meter is ready to display instantaneous flow, gas pressure, and gas temperature readings in your choice of engineering units.

Accessories included with purchase:

  • Micro-USB to USB cable for power and serial communication.
  • USB to wall adapter converter with four interchangeable prong configurations.
  • FlowVision software (free download)

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Not exactly what you’re looking for?

  • We offer several additional gas mass flow meter options, including non-portable, standard pressure drop, high-pressure, anti-corrosive, and Coriolis devices (see “models” tab below).
  • If a gas mass flow meter is not what you need, check out our other flow or pressure measurement and control solutions.
  • Still don’t see what you need? Feel free to contact us and discuss custom build options with one of our applications engineers.
Whisper™ MWB–Series performance (most products)
  • Available ranges: max 0–1000 SLPM; min 0–0.5 SCCM
  • Flow measurement range: 0.01% – 100% of full scale
  • Standard accuracy calibration, NIST-traceable: ±0.75% of reading or ±0.1% of full scale
  • Optional high-accuracy calibration, NIST-traceable: ±0.6% of reading or ±0.1% of full scale
  • Repeatability: ±(0.1% of reading + 0.02% of full scale)
  • Typical measurement response time: <10 ms
  • Warm-up time: <1 s
Whisper™ MWB–Series operating conditions
  • Compatible gases: 98 pre–loaded selectable gas calibrations; additional mixtures definable with COMPOSER™
  • Operating temperature: –10°C to +60°C
  • Full scale operating pressure: 60 PSIA
  • Full scale pressure drop (range dependent): as low as 0.07 PSID
  • Max differential pressure: 10 PSID
  • Proof pressure: 80 PSIA
  • Reference conditions: user-selectable; defaults: 25°C & 1 ATM (STP) and 0°C & 1 ATM (NTP)
Available device ranges for MWB-Series

Alicat offers Whisper portable meters with custom flow ranges from 0.5 SCCM full scale to 1000 SLPM full scale, each with a measurement range of 0.01% to 100% of full scale. Custom devices are ranged to best meet your specific application needs for full scale flow rate and operating range.

It is important to note that some device specifications vary depending on the full scale flow rate.

If you have any questions or need additional information, reach out to our applications engineers.

Device customization | Build and performance options

  • Communications protocols: Serial over micro-USB
  • Displays: monochrome or color
  • Process connections: NPT, SAE, AN, BSPP/G, welded compression, or VCR/VCO fittings
  • Elastomers: Viton, FFKM, EPDM, Silicone
  • Calibration: High-accuracy or custom
  • Performance: Flow totalizer

Accessories | Sold separately

  • Process port fittings and filters

Calibration Solutions | Calibration of an air sampling canister

Rapidly calibrate across multiple ranges and gases without carrying a computer. NIST-traceable high-accuracy calibration makes your portable a transfer standard. Whisper-Series low pressure drop enables non-intrusive volumetric flow calibration.


To minimize the pressure drop when calibrating a rotameter and ensure the best possible calibration, an Alicat MWB-Series portable flow meter can be used to maintain a pressure drop as low as 0.07 PSID at full scale.


Questions about this product?