temperature sensor for railway tunnel

heat detector with data logging direct from Wanlin Fire Protection — 12-year factory experience, WL-HD907 fully certified UL 521/EN 54-5/CE/FCC/RoHS/REACH. Key specs: Bluetooth 5.0 + 4G LTE (optional), Fixed Temperature Sensor + Compact Design, 2-year replaceable battery (1x CR123A). MOQ 100 units, 25-30 working days, OEM/ODM custom branding available. Serv···