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Handheld Particle Counter GT-521S

The GT-521S is a full-featured, battery-operated, portable particle counter that provides the functionality of a bench unit with the convenience of a handheld. This powerful device supports cumulative or differential counts, standard concentrations, total counts and count alarms. It can log particle counts locally and continuously as well as send them to a network. An aluminum enclosure provides protection from bumps and scrapes that can damage plastic instruments. A rugged carrying case is also provided.


  • 2 channels of monitoring user selectable
  • Simple & powerful menu driven functionality
  • Adjustable sample time
  • Differential or cumulative
  • Battery or AC Powered
  • 1-Year Warranty



  • Operation Manual
  • USB Cable
  • Comet Software
  • AC Adapter / Battery Charger
  • Iso-kinetic Sample Probe
  • Carrying Case
  • Zero Particulate Filter
  • NIST Certificate of Calibration


  • RH & Temperature Probe (P/N G3120)
  • Flow Meter (P/N 9801)
  • Custom Serial Cable (P/N 3228)
  • Portable Printer (P/N G3115)
  • ISO Cal 21501-4 (P/N 80849)
  • Wall / Tripod Mount (P/N 8956-1)
  • Particle View Software (P/N Particle View)


Our GT-521S allows the user to select particle sizes with two programmable count channels ranging from 0.3 to 10 microns each show differential or cumulative particle counts in real time, with selectable count units in .01 micron increments. The 521S features a 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 USB (cable supplied) or RS-232/RS-485 (optional cable) allows extensive control, including all front-panel operations. The GT-521S can store up to 8,000 sample events with outputs to printer, Excel or networked datalogging via included software (Comet). Sample history can also be viewed on the local display or download to a computer using the supplied Comet software.

The GT-521S is battery powered with 24 hours of typical (intermittent) operation or 10 hours of continuous operation from a single charge. Recharge time is approximately 2.5 hours. The GT-521S can also come with a temperature / relative humidity plug-and-play option, which immediately adds ambient temperature and relative humidity capabilities to the displayed and logged data.


Specifications are subject to change at any time.
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