non polar two wire connection

museum smoke detector direct from Wanlin Fire Protection — 12-year factory experience, WL-SFP900 smart fire detector certified CE/EN14604/EN54/UL217/UL268/FCC/QCVN. Key specs: Multi-Sensor (Smoke+Heat+CO) + 4G LTE + WiFi + Cloud Platform + Complete Installation Kit + 10-Year Design, 4G LTE Cat.1 + WiFi + Cloud Platform + Mobile APP + Complete Kit (Gateway + ···