sensor contamination reminder

business park smoke alarm direct from Wanlin Fire Protection — 12-year factory experience, WL-SFP100 smart fire detector certified UL 217/UL 268/UL 2034/UL 864/CE/EN14604/EN54/FCC. Key specs: Dual-Wavelength Photoelectric Sensing + Infrared Scattering Chamber + 4G LTE Cat.1 Cellular Communication, 4G LTE Cat.1 + IoT Cloud Platform + SMS/Push/Email Alerts + R···