Higher Security & Compact Size: Featuring an upgraded smoke sensor with the latest in photoelectric technology, this smoke alarm responds to hazardous smoke quicker than traditional alarms with an over loud alarm and a rapid flashing LED indicator,giving you extra time to control the fire or safely escape Easy to Install: This mini smoke detector has a diameter of only , so it can be unobtrusively installed anywhere easily; effortlessly mount it onto any wall or ceiling using the included screws and anchor plugs Self-Check & Silence Functions: Equipped with a low-battery warning, so you know when its time to replace the unit for safety; if non-emergency smoke (e.g., cooking fumes) causes nuisance alerts, you can easily silence them by pressing the test/silencebutton