03 Series

RKI 03 Series

The 03 Series single gas monitors are designed for LEL, O2, H2S, or CO detection. Individuals need personal protection in hazardous areas at all times without adding extra bulky equipment, and the 03 Series can provide that kind of protection at an affordable price. The GP-03, OX-03, CO-03, and HS-03 models are personal single gas monitors designed for protection from exposure to combustible hydrocarbons, oxygen deficiency, hydrogen sulfide, or carbon monoxide.
  • Available for LEL, O2, H2S, or CO
  • Operates 3,000 hours on alkaline (GP-03 up to 35 hours)
  • Pocket size 2.1” x 2.6” x 0.9”
  • Lightweight, 2.8 ounces
  • IP-67
  • Data log from 5 to 300 hours
  • Audible / visual / vibration alarms
  • Automatic backlight
  • Peak Hold, STEL & TWA
  • Intrinsically safe, ATEX & CSA
  • 3 Year warranty H2S & CO
  • 2 Year warranty LEL & O2
  • Hazardous Material
  • Mining
  • Tunnels
  • Refineries / Petrochemical
  • Water / Wastewater Treatment
  • Pharmaceuticals
  • Utilities
  • Chemical Plants
  • Fire Services
Model NameCO-03HS-03OX-03GP-03
Gas DetectedCarbon Monoxide (CO)Hydrogen Sulfide (H2S)Oxygen (O2)Combustible gas
Detection PrincipleElectrochemicalGalvanic cellCatalytic combustion
Detection Range
0 – 500 ppm
(1 ppm)
0 – 100 ppm
(0.5 ppm)
0 – 40% vol.
(0.1% vol.)
0 – 100% LEL
(1% LEL increments)
Alarm Set Points1st 25 ppm1st 5.0 ppmLow 19.5% vol.1st 10% LEL
2nd 50 ppm2nd 30.0 ppmHigh 23.5% vol.2nd 50% LEL
TWA 25 ppmTWA 1.0 ppmOver 40.0% vol.Over 100% LEL
STEL 200 ppmSTEL 5.0 ppm
Over 500 ppmOver 100.0 ppm
Alarm TypesGas alarms:1st and 2nd (user adjustable), OVER alarm, STEL and TWA
Trouble alarms:Sensor connection, low battery circuit failure, and calibration range error
Alarm MethodsGas 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 SamplingDiffusion
Response TimeT90 in 30 secondsT90 in 20 seconds
(Alarms within
5 seconds when exposed to 12% O2)
T90 in 30 seconds
Accuracy which ever is greater± 5% of reading or ± 5 ppm CO± 5% of reading or ± 2 ppm H2S±0.5% O2± 5 of reading or
± 2% LEL
Power OptionsAlkaline dry cell (2-AAA size)Alkaline dry cell (2-AAA size)
Ni-MH battery
Continuous OperationAlkaline dry cell: more than 3,000 hours (at 25°C, no backlight)Alkaline: 35 hrs
Ni-MH: 30 hrs
Safety RatingATEX/IECEx approved. CSA classified, “C/US”, as intrinsically safe, Class I, Division 1, Groups A, B, C, D
Dimensions & Weight2.1” W x 2.64” H x 0.94” D, (54 x 67 x 24 mm); 2.8 ounces (80 g)
DisplayDigital 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 AccessoriesRubber protective boot
Alligator clip
Data logging software
Alkaline batteries
Optional AccessoriesCalibration adapter
Charger unit
Calibration kit
Belt clip
Data logging download cable
Wrist strap
Special FunctionsManual backlight for LCD (automatically lit during alarm)
Peak hold, STEL & TWA
Warranty3 Year warranty2 Year warranty
Part NumberDescription
07-6031Gasket for battery compartment cover on 03 series
07-6032Gasket between front and rear case of 03 series
07-6033Sensor gasket for 03 series
07-6034Rubber sheet around buzzer on main board of 03 series
10-1105-01Screw, M 2 x 8 mm, pan head phillips, with washer, SUSXM7, for 03 series
13-0112RKWrist strap
13-0121Alligator Clip for 03 series (requires 13-0204RK for installation)
13-0122Belt Clip for 03 series
13-0204RKSpring bar with outer tube for 03 Series and wrist band of GasWatch 2/GasWatch 3
13-1116Screw for battery compartment cover of 03 series
15-0500Battery contact short for 03 series
15-0501Battery contact piece (-) for 03 series
15-0502Battery contact piece (+) for 03 series
20-0325Rubber boot for 03 series
21-1908Battery compartment cover for 03 series
21-1909Battery contact holder for 03 series
21-1910Rear case for GP-03 and OX-03
21-1911Rear case for CO-03 and HS-03
21-1912Front case for 03 series
21-1913Front case assembly for 03 series
29-0652Label, front for GP-03
29-0653Label, front for OX-03
29-0654Label, front for CO-03
29-0655Label, front for HS-03
29-6100Water immersion sensing seal, adhesive backed for 03 series, GX-6000, and SP-220
30-1055Vibration motor for 03 series
33-0175Hydrophobic filter, PF020 for 03 series/RP-2009/GasWatch 3
33-7106RKCharcoal filter disk for CO sensor, strip of 5, for CO-03, GasWatch 2, GasWatch 3
49-1110RKBattery, alkaline, AAA
49-1312Battery, Ni-MH, AAA, Eneloop by Panasonic
51-1130LCD Module for 03 series
57-1282Main PC board assembly, GP-03
57-1283Main PC board assembly, OX-03
57-1284Main PC board assembly, CO-03
57-1285Main PC board assembly, HS-03
81-1146Calibration adapter for 03 series
81-1146-01Calibration adapter for 03 Series with velcro strap and 1 ft tube on inlet
ES-1821Sensor, Carbon Monoxide (CO) for GX-2009/GX-2012/GX-6000/CO-03/GasWatch 2/Gas Tracer
ES-1827ISensor, Hydrogen Sulfide (H2S) for GX-2009/GX-2012/GX-6000/HS-03/GasWatch 2
NC-6264ASensor, LEL, for GX-2009/GX-2012/GX-6000/GP-03/Gas Tracer
OS-BM2Sensor, Oxygen (O2) for GX-2009/GX-2012/GX-6000/GasWatch 2/OX-03/Gas Tracer
OS-BM2-05Sensor, Oxygen (O2) for GX-2009/GX-2012/GX-6000/GasWatch 2/OX-03/Gas Tracer (pack of 5)