This Kidde smoke alarm is a reliable and essential addition to any home security system. With a power source of batteries, it comes with a 9VDCPESA ST-11 model, featuring a photoelectric smoke sensor and battery backup. The unit is sealed and comes with a battery included, making it easy to instal and use. Measuring 10cm in diameter and 3cm in depth, this white smoke alarm is a unit type that emits an operating sound rating of 85dB. It is perfect for detecting smoke in any room, and its features include a single battery and a custom bundle. This smoke alarm is a great investment for anyone who values home security.