... Mine Underground Coal Mine, Pipeline, and Explosive Portable Multi-Gas Detector for CO, H2S, O2 and LELNatural ... method: Natural diffusionGas sensor type: Catalytic and electrochemicalDetecting gas: Combustible gas, H2S, CO, O2Accuracy: ≤±5% F.S ... time: ≥ 8h continuously (without alarming)Gas Sensor Life: 2 yearsExplosion-proof grade: Ex ibd IICT3Protection Grade: IP65 BX616 Portable Gas Detector