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GX-3R Multi Gas Detector includes LEL/O2/CO/H2S sensors, rubber boot, charger and calibration adapter

The GX-3R is the worlds smallest 4 gas monitor weighing only 3.52 ounces and can comfortably be clipped within a worker’s breathing zone.


SKU 772-RA-C Categories , Tag



The GX-3R Multi Gas Detector is the worlds smallest 4 gas monitor weighing only 3.52 ounces and can comfortably be clipped within a worker’s breathing zone (2.2” W x 2.55” H x 1.02” D). It simultaneously monitors and displays LEL combustibles, O2, CO (Hydrogen compensated CO also available), and H2S.

The GX-3R represents the latest evolution of gas detection technology utilizing a new generation of micro sensors. The LEL sensor has a unique design with two active filaments in one sensor to increase it’s resistance to silicone poisoning. If one filament gets poisoned the second filament takes over. The new O2 sensor is electrochemical with a 3 to 5 year life span. H2S and CO are now available in a combo micro sensor.

Safety supervisors will appreciate the non-compliance indicator. The instrument flashes it’s 3 LED lights every 30 seconds in the following conditions; if the instrument has not been bump tested, or if calibration is due, or if there was a gas alarm event. The 3 LED lights will continue to flash once every 30 seconds until the non-compliance condition has been resolved. The 30 second interval is adjustable.

OSHA defines the breathing zone as a ten inch radius around the worker’s nose and mouth, and requires that worker exposure monitoring air samples be collected in the breathing zone. Air sampling filters may be attached to the collar or lapel.  Traditionally this means only a single gas monitor would be small enough for a worker to practically wear a gas monitor ‘In the breathing zone’. Now there is a 4 gas monitor smaller than many single gas monitors.


Tags: CO Carbon Monoxide Gas Detector, H2S Hydrogen Sulfide Gas Detector, O2 Oxygen Gas Detector

Additional information

Weight .8 lbs


  • Smallest & lightest 4 gas monitor
  • Simultaneous detection of 4 gases; LEL, O2, H2S & CO
  • H2 Compensated CO sensor available
  • Simple 2-button operation
  • Alarms: audible, visual, & vibration
  • 3 user adjustable alarm levels
  • 25 hours of operation (Lithium-ion battery)
  • Water and dust resistant design, IP66/68
  • 3 Year warranty


Sample Method Diffusion or clip-on motorized pump, optional
Response Time T90 in 30 seconds
Alarm Gas Alarm: 1st, 2nd, 3rd (user adjustable), OVER alarm, STEL and TWA
Trouble Alarm: Sensor connection, low battery, circuit failure and calibration rang error
Battery Lithium-Ion Battery, about 25 hours of use after a full 3 hour charge
Display Digital LCD, gas name & concentration, auto backlighting during alarm, operation icon, battery icon
Alarm Flashing LEDs
Audible: 100 dB @ 30cm
Datalogging Logs user ID, station ID, calibration & bump history, alarm events, alarm interval trends
Enclosure Dust and water resistant with IP-66/68 rating
Temperature -4 to 122°F
Humidity 10% to 90% relative humidity (non-condensing)
Intrinsic Safety ATEX and CSA
Size 2.2″ x 2.55″ x 1.02″
Weight 3.52 ounces
Warranty 3 Year warranty

Sensor Specifications

0 – 100% LEL
10% /25 %
Carbon Monoxide (CO)  0 – 2,000 ppm 25 ppm/50 ppm
Hydrogen Sulfide (H2S)  0 – 200.0 ppm  5 ppm/30.0 ppm
Oxygen (O2)  0 – 40% Vol  19.5 % Vol/18.0% Vol


GX-3R Multi Gas Detector datasheet

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