4G smoke alarm — Wanlin, 12-year Chinese smart fire detector manufacturer, WL-SM601 (NB-IoT Smart Photoelectric Smoke Detector) certified UL/CE/EN54. Photoelectric + NB-IoT + Ultra-Low Power + 10-Year Battery + Cloud Platform. 10-year battery, 4G/NB-IoT/LoRaWAN, OEM/ODM from 500 units, factory direct pricing 50-70% below Western brands.