heat detector for cable tunnel

real time temperature monitoring direct from Wanlin Fire Protection — 12-year factory experience, WL-HD900 fully certified UL 521/EN 54-5/CE/FCC/RoHS/REACH. Key specs: 4G LTE Cat.1 + WiFi, Fixed Temperature + Rate-of-Rise Dual Sensor (57°C / 135°F), AC powered + 72h backup battery. MOQ 100 units, 25-30 working days, OEM/ODM custom branding available. Serv···