gas alarm with pre alarm and main alarm

shipping container home gas alarm direct from Wanlin Fire Protection — 12-year factory experience, WL-GA202 4G gas detector certified CE/EN50194/UL2075/FCC. Key specs: Catalytic Gas Sensor + Photoelectric Smoke Sensor + 4G Cat.1 Dual-Channel Communication, 4G LTE Cat.1 + Cloud Platform + Dual Alarm Channel (Gas + Smoke) + SMS/Push/Email + Valve Control. Cat···