battery replacement reminder smoke alarm

instant notification smoke alarm direct from Wanlin Fire Protection — 12-year factory experience, WL-SM604 4G standalone smoke detector certified CCCF/GB 20517-2006/CE/UL 217/EN 14604. Key specs: Dual Light Path Photoelectric + AI False Alarm Algorithm + 4G Cat.1 + Edge Computing, 4G LTE Cat.1 + AI Cloud Platform + Smart Push + Predictive Maintenance + OTA ···