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This product has been discontinued

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Smallest Four Gas Personal Monitor

GX-2001 Gas MonitorAfter 60 years of breakthroughs in gas detection and sensor technology, RKI is proud to introduce the smallest and most affordable 4-gas monitor in the world, the GX-2001. Weighing only 6 ounces and about the size of a pager (2.8" H x 2.2" W x 1.1" D), the GX-2001 simultaneously monitors combustibles, oxygen, carbon monoxide, and hydrogen sulfide.

The GX-2001 is armed with standard features like autocalibration, datalogging, rechargeable Ni-MH batteries, a unique vibration alarm, STEL / TWA readings, peak hold and auto backlighting at alarm on a large LCD display, and it even tells the time. All of these controls and features are operated through 3 simple glow in the dark buttons. Utilizing either of the GX-2001's chargers, the standard charger or datalogging / charger station, it's Ni-MH batteries will fully recharge in 90 minutes. Also available is the datalogging software program which is Windows 95, 98, ME compatible.

  • Features
  • Specifications
  • Downloads
  • Video


  • Simultaneous detection of 4 gases LEL, O2, H2S, & CO
  • Smallest 4 gas monitor on the market 2.8” H x 2.2” W x 1.1” D,
    6 oz
  • Audible, Visual, & Vibration alarms
  • Alarm trend data
  • Datalogging standard
  • Autocalibration
  • Ni-MH batteries recharge in 90 minutes
  • Continuously operates for up to 18 hours
  • Large LCD display screen
  • Automatic backlighting at alarm
  • High impact, RFI shielded body
  • STEL and TWA readouts
  • Peak hold readouts
  • Continuously displays current time
  • Intrinsically safe, CSA, C / US approved
  • 2 year warranty


  • Personal monitoring
  • Confined spaces
  • Refineries / petrochemical
  • Utilities
  • Chemical plants
  • Hazardous material
  • Water / wastewater treatment
  • Fire services
  • Mining

GX-2003 manhole

The GX-2001 is also designed around the world's smallest gas sensors. Utilizing catalytic combustion, electrochemical and galvanic sensor technologies, each miniaturized sensor is manufactured with the same high quality control that has made Riken sensors and instruments the most reliable and long lasting monitoring devices in the industry.

Gas Detected
Combustible Gases (Methane cal standard)
Oxygen (O2)
Hydrogen Sulfide (H2S)
Carbon Monoxide (CO)
Detection Principle Catalytic combustion Galvanic cell Electrochemical cell
Detection Range (Increments) 0~100% LEL
(1% LEL)
0~40.0% Vol.
(0.1% Vol.)
0~100.0 ppm
(0.5 ppm)
0~500 ppm
Sampling Method Diffusion sampling, attachable sample drawing pump (RP-6) and hand aspirator optional
Display Digital LCD with 7 segments, auto backlight at alarm display automatically cycles every 3 seconds reading each gas, immediate reading for alarm condition
Preset Alarms (User Adjustable)
1st alarm 10% LEL
2nd alarm 50% LEL
Over alarm 100% LEL
Low alarm 19.5%
High alarm 23.5%
Over alarm 40.0%
1st alarm 10 ppm
2nd alarm 30 ppm
TWA alarm 10 ppm
STEL alarm 100 ppm
1st alarm 25 ppm
2nd alarm 50 ppm
TWA 25 ppm
STEL alarm 400 ppm
Over alarm 500 ppm
Kinds of Alarms
Gas alarms: 2 increasing alarms, STEL, TWA, over scale
Trouble alarms: Sensor connection, low battery, circuit error, calibration range error
Display of Alarm
Gas alarm: Blinking LEDs, intermittent buzzer, blinking gas value, vibration
Trouble alarm: Blinking LEDs intermittent buzzer, display of error message
Special Functions
Manual back light LCD (Automatic at alarm)
Peak hold
Continuous display of current time
Data logging (40 hours)
Alarm trend
Direct charging
Operating Temp. & Humidity -20°C~+40°C (-4 to 104°F), 0 to 85% RH, non-condensing
Response Time Within 30 seconds (T90)
Continuous Operation Up to 18 hours
Power Source Direct charging Ni-MH battery pack, (2.4VDC)
Safety Design CSA classified, "C/US", as Intrinsically Safe. Exia. Class I, Groups A, B, C, & D. Class I, Zone 0, Group IIC. Temperature Code T3C.
Dimensions & Weight Approx. 72 (H) x 56 (W) x 27 (D) mm (2.8” H x 2.2” W x 1.1” D), approx. 140 g (6 ounces)
Case Material Dust & weather resistant. RFI shielded high Impact plastic and stainless steel
Controls Three glow in the dark buttons: POWER / MODE, DISP, AIR
Warranty Two year material and workmanship
Required Accessories Battery Charger or Datalogging / Charger Station with cable and software for datalogging
Optional Accessories
(1) Charging station with PC communication function for datalog downloading
(2) Communication computer cable
(3) Communication software (Windows 95, 98, & NT)
(4) Automatic calibration station
(5) Remote Sample Drawing Pump, RP-6 Model
(6) Hand aspirated sample draw with hose and probe

Specifications subject to change without notice. 

Introduction | Description | Start Up | Operation | Calibration Mode
Bump Test | Set Alarm Points | RP-6 Pump | Maintenance

This video is also available on Youtube and CD (by request)


Smallest Four Gas Personal Monitor

GX-2009 Portable Gas Monitor Smallest and most affordable 4-gas monitor in the world.

LEL, O2, H2S, & CO



Four Gas Confined Space Monitor

GX-20122 Operating Modes:
Confined Space
& Bar Hole

Monitors LEL, and % volume methane, O2, CO and H2S

Internal sample drawing pump with up to 50' range