Help keep your family safe with this battery powered smoke alarm featuring a Photoelectric sensor for smoke detection. -- Compatible with other Safe-Tech detectors to create a wireless safety network.(CO detector, Remote controller, WiFi interconnected smoke alarm) -- We suggest a maximum of 20-50 pcs connected on one floor of the building for best connection performance. If one alarm goes off, all connected alarms will go off. -- The alarm will cover the whole house even if you are in another room, A loud 85-decibel siren is designed to wake even the soundest sleepers. -- With built-in sealed 3V Li battery can last up to 10 years, no battery replacement within 5-8 years, save the money and time for replacing the battery, Longer battery life, safety guarantee! -- Battery operated alarm unit provides continuous monitoring even if there's a power failure. -- Test and Silence button. -- Easy to install. -- CE EN14604/AS3786 ROHS listed Product Details 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 Operating Frequency: RF433 MHz Standby current: