The RKI GX-3R is the world's smallest 4-gas monitor, weighing only 3.52 ounces. It simultaneously monitors LEL combustibles, O₂, CO, and H₂S. The kit includes the detector, 100-240 VAC charger, tubing, screwdriver, and carrying case. Optional accessories include a 34AL cylinder of calibration gas and RP-3R sampling pump with 10 ft hose and probe.

The detector features simple 2-button operation, non-compliance indicator, three user-adjustable alarm levels, and audible/visual/vibration alarms. It has an impact-resistant body with removable rubber boot and large LCD auto-backlit display. Response time T90 within 30 seconds. The GX-3R is intrinsically safe with ATEX and IECEx approvals.