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Home Products Dust (Indoor/Outdoor) Handheld Aerosol Monitor Met One Air Quality GT-521S Two Channel Particle Counter

Met One Air Quality GT-521S Two Channel Particle Counter

Met One Air Quality GT-521S Two Channel Particle Counter

Bench unit performance in the palm of your hand  Big Performance, Small Size

The GT-521S is a full-featured, battery-operated, portable laser particle counter that provides the functionality of a bench unit with the convenience of a handheld! It can datalogging particle counts continuously or send them to a network.

Dual Programmable Particle Channels

Two programmable particle channels with a range of 0.3 – 5.0 microns each show differential or cumulative particle counts in real time, with selectable count units.

Simple and Powerful Menu-Driven Command Set

A simple touch of a button sets particle sizes, sample time, alarm settings, and basic setup parameters such as date/time and communications settings. Remote operation via RS-232 or RS-485 communications ports allows extensive control, including all front-panel operations.

Flexible Data Interfaces

Stores up to 4,000 records for printer output, Excel® formatted output, or networked datalogging via the included single computer software (GT-Comm).

Temperature and Relative Humidity Option

A plug-and-play option that immediately adds ambient temperature and relative humidity capabilities to the displayed and logged data.


  • Controlled Environments
  • Indoor Air Quality
  • Process Control
  • HVAC Applications
  • Filter Testing
  • Compliance Testing
  • Emission Sourcing
  • Remote Sampling
  • QA Programs


  • OPERATING PRINCIPLE   :  Counts individual particles using scattered laser light


  • Particle Size Range  :  2 channels—from 0.3 to 5.0 μm (selectable in 0.1 μm increments)
  • Concentration Range  :  0 – 3,000,000 particles per cubic foot (105,900 particles/L)
  • Accuracy   :  ± 10%, to calibration aerosol
  • Sensitivity  :  0.3 μm
  • Flow Rate  :  0.1 cfm (2.83 lpm)
  • Sample Time Adjustable  :   6 to 999 seconds
  • Hold Time Adjustable  :   1 to 999 seconds


  • Light Source  :  Laser diode, 30 mW, 780 nm
  • Power  :  6V Ni-MH self-contained battery pack—provides 8 hours of typical
  • intermittent operation, up to 5 hours continuous use
  • AC Adapter/Charger  :  AC to DC module, 100 – 240 VAC to 9 VDC @ 350 mA typical
  • Communications  :  RS-232 or RS-485 Half Duplex
  • Certifications  :  Meets or exceeds CE, ISO, ASTM, and JIS international Certifications


  • Display  :  16-character × 4–line LCD
  • Keyboard  :  7-key membrane type


  • Size  :  Height 6.25" (15.9 cm) Width 4.0" (10.2 cm) Thickness 2.1" (5.4 cm)
  • Weight  :  1.94 lb - 31 oz (0.88 kg)


  • Operating Temperature  :  0° to +50°C
  • Storage Temperature  :  -20° to +60°C

ACCESSORIES   :  Supplied Operation Manual, Custom Serial Cable, Communication Software (GT-Comm), AC to DC Converter Module with IEC AC Power Cord, Isokinetic Sample Probe, Screwdriver, Carrying Case & Zero Particulate Filter.

OPTIONAL   :  RH & Temperature Probe (Met One Part Number G3120) Flow Meter (Met One Part Number 9801) Portable Printer (Met One Part Number G3115)

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