Manufacturer: RKI Instruments
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**This instrument has been discontinued by RKI, but replacement parts and sensors may still be available.  Please reach out to us if you're looking to repair your existing GX-2003 or if you'd like help finding a comparable replacement.**  

Built around high-quality micro-sensor technology, the GX-2003 is RKIs smallest personal 4-in-1 gas monitor with a built in sample pump. Weighing only 11 ounces, it has many features which set the GX-2003 apart from the competition. For example, it can monitor the standard confined space gases (LEL combustibles, Oxygen content, Carbon Monoxide, and Hydrogen Sulfide), and it can also measure 100% volume Methane and dynamically display either % LEL, or % volume with its auto-ranging ability.

Key Features

  • Three operating modes: Normal, Bar Hole, and Leak Check
  • Monitors LEL, and % volume methane, O2, CO and H2S
  • Barhole mode tests for peak methane and oxygen levels
  • Leak detect mode offers high sensitivity tests for ppm level natural gas leaks
  • 0 to 100% volume Methane option
  • Auto-ranging display of % volume and % LEL
  • Internal sample drawing pump with up to 40' range
  • Vibration, visual, and audible alarms
  • Automatic backlight during alarms
  • Calibration reminder with lock out option
  • Ni-MH or alkaline power source (interchangeable)
  • Quick charge (complete charge in 90 minutes)
  • Glove friendly glow in the dark buttons
  • Alarm latching or non-latching
  • High impact protective rubber boot
  • Up to 600 hours of datalogging with alarm trends
  • Autocalibration or single calibration
  • TWA and STEL readings with lunch-break mode
  • Intrinsically safe, CSA, C/US classified

Sampling Method

  • Internal sample pump, flow rate nominal 0.5 LPM, includes hydrophobic filter


  • Digital LCD with 7 segments
  • Auto backlight during alarm

Alarm Method

  • Gas alarms: 1st and 2nd (user adjustable), STEL, TWA and OVER
  • Trouble alarms: Sensor connection, low battery, low flow, circuit trouble and calibration error

Types of Alarms

  • Gas alarms: Flashing lights, two tone buzzer, and vibration
  • Trouble alarms: Flashing lights, trouble displayed, intermittent buzzer, and vibration

Operating Temperature & Humidity

  • -20° C ~ + 50° C (-4 to 122° F)
  • 0 to 85% RH, non-condensing

Response Time

  • Within 30 seconds (T90)

Continuous Operation

  • Alkaline battery: 14 hours
  • Ni-MH battery: 16 hours (fully charged)

Power Source

  • Ni-MH battery pack, direct or separate charge
  • 3 AA Alkaline dry cell batteries
  • Interchangeable

Safety Design

  • CSA classified, “C/US”, as intrinsically safe. Class I, Division 1, Groups A, B, C, D


  • Approx. 171 (H) x 65 (W) x 39 (D) mm (5.6"H x 2.5"W x 1.5"D)


  • Approx. 310 g (11 ounces)

Case Material

  • Dust & splash resistant
  • RFI shielded high impact plastic with protective rubber boot


  • Five buttons: POWER / ENTER, DISPLAY, AIR, RESET, SHIFT (glow-in-the-dark)


  • 1, 2, 3, 4, or 5 sensor units
  • Ni-MH or alkaline battery options

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