Using a sensitive temperature sensor, when the ambient temperature exceeds 136.4 F (58 C), it can quickly emit a sound greater than 85dB and a warning light alarm. -- Sound and light alarms are issued to warn you more comprehensively of danger. -- Suitable for horizontal mounting in living room, stair crawl space, storage room, kitchen, boiler room, power generation room, drying room and smoking room, where the relative humidity is often greater than 95%. -- (Dusty workshops and other spaces where smoke detectors are not suitable for installation.) -- Please test the product once a week to ensure that the product is operating normally. -- Clean around the temperature probe once a year to ensure that there are no blockages. Product Details Type: Radio link, Interlinked Alarm Mode: Siren with Flash Colour: White Material: Polyurethane Dimensions: 10.8 x 3.7 cm; 4.25 x 1.46 inch Weights: 175 G Power: Sealed 3.0V CR123A Lithium Battery (none-replaceable) Battery Life: 10 Year Type of Sensor: Photoelectric Wireless Signal: 433.92Mhz GFSK Operating Frequency: RF433 MHz Working Temperature: -10 ~+50 C Relative Humidity: