The SAFE-TECH SM Series Interlinked Heat Alarm offers a convenient wireless solution for your home's fire and safety system. This model, SM-22HI, features easy Test & Hush functions and is ideal for homes, small offices, caravans, and holiday homes. It is compliant with Construction Products Regulation (EU) No. 305/2011 and Regulation (EU) No: 2014/53/EU, and approved to BS 5446-2:2003 by Intertek. The alarm is powered by a sealed 3.0V lithium battery with a 10-year life, and the product also has a 10-year life. It uses a thermistor sensor with a heat sensitivity of 54-72℃. The alarm draws less than 30uA on standby and less than 70mA when alarming. It operates within a temperature range of -10℃ to +50℃ and up to 95% relative humidity. The wireless signal is an encrypted RF433.92Mhz GFSK, with a low battery alarm threshold of 2.6±0.1V. The siren produces an alarm sound pressure of ≥85dB at 3m, with an RF distance of >25m. The alarm mode includes a siren with red LED flash. The product dimensions are 12 x 4.7 cm and it comes with a 2-year warranty. Package contents include 1 x SM-22HI Interlinked Heat Alarm, a mounting bracket, screws with wall plugs, a user manual, and a quick start guide. Please note that battery life may vary based on configuration and usage. All images are for illustration purposes; actual product size and color may vary slightly.