Kidde 5 Battery Ionization Smoke Alarm with Test Button model I9030 features advanced sensor technology to help protect you and your family from the dangers of smoke and fire. Ionization sensing technology allows the smoke alarm to detect invisible fire particles (associated with flaming fires) sooner than photoelectric alarms. Kidde strongly recommends that both ionization and photoelectric smoke alarms be installed to help ensure maximum detection of the various types of fire that can occur within the home. Operating on a single 9-volt alkaline battery this smoke detector provides continuous protection from smoke or fire even during power outages. The smoke detector is easy to install on a wall or ceiling; to ensure proper installation the test/silence button will electronically simulate the presence of smoke and cause the unit to sound. This Kidde smoke detector is dependable and reliable giving you the warning you need to prevent disaster or damage to your home. It is ideal for your house or apartment and will give you peace of mind that you can keep your family safe in an emergency. UL Certified with a 3-year limited warranty.