The RKI Instruments GX-3R is recognized as the world's smallest 4-gas monitor, weighing only 3.52 ounces. Its compact dimensions (2.2" W x 2.55" H x 1.02" D) allow it to be comfortably clipped within a worker's breathing zone. It simultaneously monitors and displays levels of LEL combustibles, O2, CO (a hydrogen-compensated CO sensor is also available), and H2S.

The GX-3R represents the latest evolution of gas detection technology, utilizing a new generation of micro-sensors. The LEL sensor features a unique design with two active filaments in one sensor to increase its resistance to silicone poisoning; if one filament is poisoned, the second filament takes over. The new O2 sensor is electrochemical with a 3 to 5-year lifespan, and H2S and CO are now available in a combo micro-sensor.

Key features include simple 2-button operation, a non-compliance indicator, and three user-adjustable alarm levels with audible, visual, and vibration alarms. It has an impact-resistant body with a removable rubber boot and a large, auto-backlit LCD display. Applications include personal monitoring, confined space entry, refineries/petrochemical, utilities, oil and gas, water/wastewater, fire services, and construction.