maze sensor structure smoke detector

NB-IoT standalone smoke detector direct from Wanlin Fire Protection — 12-year factory experience, WL-SM608 4G standalone smoke detector certified CCCF/GB 20517-2006/CE/UL 217/EN 14604. Key specs: Dual Light Path Photoelectric + 4G Cat.1 + Cloud Platform + Complete Installation Kit + 10-Year Design, 4G LTE Cat.1 + Cloud Platform + Mobile APP + Complete Kit (D···