The RKI Instruments 03 series single gas monitor is a pocket sized gas monitor designed for protection from exposure to combustible hydrocarbons, oxygen deficiency, hydrogen sulfide, or carbon monoxide.

The O2, CO, and H2S versions can be operated continuously for at least 3,000 hours on two AAA alkaline batteries. The GP-03 for LEL operates for 35 hours on alkaline and 30 hours on rechargeable Ni-MH batteries.

RKI 03 series single gas monitors are safe for use in hazardous locations, and are classified as intrinsically safe ATEX/IECEx and by CSA to US and Canadian standards for Class I, Division 1, Groups A, B, C, and D atmospheres.