SPECIFICATION: 1. Operating Voltage:AC220V, or AC110V; DC12~20V 2. Working temperature: -10degree~50 degree 3. Alarm density: Coal gas: 2000ppm+/- 30%, natural gas: 2000ppm+/-30%,Liquid petroleum gas: 5000ppm+/-30%, 5. Operating Frequency: 433 MHZ/315MHZ (optional) 4. Responding time: less than 2 seconds 6. Net Weight: 0.2kg 7.Size: 115mm(L)¡Á71mm(W)¡Á43mm(H)