convention center smoke alarm

group home smoke detector — Wanlin, 12-year Chinese smart fire detector manufacturer, WL-GA201 (NB-IoT Smart Gas Detector) certified UL/CE/EN54. Electrochemical/Semiconductor + NB-IoT + Cloud + Valve Control + 5-Year Battery. 10-year battery, 4G/NB-IoT/LoRaWAN, OEM/ODM from 500 units, factory direct pricing 50-70% below Western brands.