gas alarm with pre alarm and main alarm

combustible gas detector direct from Wanlin Fire Protection — 12-year factory experience, WL-GA205 4G gas detector certified CE/EN50194/UL2075/FCC. Key specs: Infrared Gas Sensor + LoRaWAN Long Range + Low Power + Dual Communication, LoRaWAN + IoT Gateway + Cloud Platform + Long Range (up to 15km) + 4G Cat.1 Backup + Battery Optimized. Catalytic/infrared se···