... , diffusion (which can increase pump into the pump suction)2, LCD digital display3, sound, light, vibration alarm at the same4 DC3 ... (can be added into the pump suction pump)6, Display: LCD display7, alarm error: ≤ ± 5% (F.S)8, Alarm mode: sound ... , metallurgy security ring, Chemical Services and other occasions Combustible Gas Detector