GP-03 Series smallest combustible gas detectors - LEL Monitor by RKI Instruments


Combustible Single Gas Monitor


  • Operates 35 or 30 hrs on alkaline / Ni-MH
  • Pocket size 2.1”(W) x 2.6”(H) x 0.9”(D)
  • Light weight 2.8 ounces
  • Impact, dust, and water resistant (IP-67)
  • Replaceable rubber boot
  • Data log 5 to 300 hours with adjustable intervals
  • Audible / visual / vibration alarms
  • Automatic backlight
  • Peak Hold, STEL & TWA
  • Low battery alarm
  • Intrinsically safe, ATEX, CSA
  • 2 Year warranty
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LEL monitor

Individuals need personal protection in hazardous areas at all times without adding extra bulky equipment, and the GP-03 can provide that kind of protection at an affordable price. The GP-03 is a personal single gas monitor designed for protection from exposure to combustible hydrocarbons.

The GP-03 operates for 35 hours on alkaline and 30 hours on rechargeable Ni-MH. The GP-03 model has 2 preset alarms that are user adjustable. It is also equipped with visual, audible, and vibration alarms as standard. The replacement sensor is inexpensive, easily field replaceable, and is interchangeable with other popular RKI instruments like the GX-2009 and GX-2012. The LEL sensor has a life expectancy of over 2 years.

The GP-03 is impact, dust, and water resistant with an IP-67 rating. The GP-03 is safe for use in hazardous locations, classified as intrinsically safe ATEX/IECEx and by CSA to U.S. and Canadian standards for Class I, Division 1, Groups A, B, C, and D atmospheres.


  • Hazardous Material
  • Mining
  • Refineries / Petrochemical
  • Utilities
  • Chemical Plants
  • Fire Services


Model Name GP-03
Gas Detected Combustible gas
Detection Principle Catalytic combustion
Detection Range
0 – 100% LEL
(1% LEL increments)
Alarm Set Points 1st 10% LEL
2nd 50% LEL
Over 100% LEL
Alarm Types Gas alarms: 1st and 2nd (user adjustable), OVER alarm, STEL and TWA
Trouble alarms: Sensor connection, low battery circuit failure, and calibration range error
Alarm Methods Gas alarm: Flashing LED’s, intermittent buzzer, flashing gas value, and vibration
Trouble alarm: Flashing LED’s, intermittent buzzer, and display of error message
STEL & TWA alarms: Flashing LED’s, intermittent buzzer, flashing gas value, and vibration
Gas Sampling Diffusion
Response Time T90 in 30 seconds
(which ever is greater)
± 5% of reading or ± 2%
Data Logging 10 second intervals = 5 hours, 5 minute intervals = 150 hours, 10 minute intervals = 300 hours
Instrument records alarms, alarm trends, gas readings, calibration & bump test history, instrument information and settings.
Battery Options Alkaline dry cell (2-AAA size) Ni-MH battery
Continuous Operation Alkaline: 35 hours
Ni-MH: 30 hours
Safety Rating ATEX/IECEx approved. CSA classified, “C/US”, as intrinsically safe, Class I, Division 1, Groups A, B, C, D
Enclosure Dust and water resistant with IP-67 rating
Dimensions & Weight 2.1” W x 2.64” H x 0.94” D, (54 x 67 x 24 mm); 2.8 ounces (80 g)
Display Digital LCD, gas name & concentration, auto backlighting during alarm, operation icon, battery icon
Operating Temp. & Humidity -4°F ~ 122°F (-20°C ~ 50°C);
Humidity below 90% RH (non-condensing)
Standard Accessories • Rubber protective boot • Alligator clip • Data logging software
• Alkaline batteries • Wrist strap
Optional Accessories • Calibration cap • Charger unit • Wrist strap • Calibration station
• Calibration kit • Belt clip • Data logging download cable
Special Functions • Manual backlight for LCD (automatically lit during alarm)
• Peak hold, STEL & TWA
Warranty 2 Year warranty



Part # Description
ES-1821 CO sensor
ES-1827I H2S sensor
NC-6264A LEL sensor
OS-BM2 O2 sensor
07-6031 Gasket for battery lid
07-6032 Gasket between top case and bottom case
07-6033 Gasket for sensor
07-6034 Rubber sheet, Black,
10-1105-01 Cross-recessed pan head screw M2×8 SUSXM7
13-0112RK Hand strap
13-0121 Alligator clip assembly with ring
13-0122 Belt clip
13-0204RK Spring pin for clip
13-1116 Screw for battery lid
15-0500 Battery contact short
15-0501 Battery contact piece (-)
15-0502 Battery contact piece (+)
20-0325 Rubber protection cover, Black
21-1908 Battery lid
21-1909 Battery contact piece holder
21-1910 Bottom case (GP-03/OX-03)
21-1911 Bottom case (CO-03/HS-03)
21-1912 Top case
21-1913 Top case asssembly
29-0652 Panel sheet RKI version (GP-03)
29-0653 Panel sheet RKI version (OX-03)
29-0654 Panel sheet RKI version (CO-03)
29-0655 Panel sheet RKI version (HS-03)
29-6100 Water immersion sensing seal
30-1055 Vibration motor
33-0175 Hydrophobic filter for sensor
33-7106RK H2S scrubber filter for CO sensor, strip of 5
49-1110RK Alkaline battery AAA (2 required)
49-1312 Ni-MH battery AAA (2 required)
51-1130 LCD module
57-1282 Main PCB assembly (GP-03)
57-1283 Main PCB assembly (OX-03)
57-1284 Main PCB assembly (CO-03)
57-1285 Main PCB assembly (HS-03)
81-1146 Calibration adapter


Specifications subject to change without notice.

Training Video

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