The First Alert SA303 Smoke Alarm is a battery-operated ionization sensor designed to detect smoke quickly and effectively. It operates on a single 9-volt battery, which is included with the purchase. This alarm meets UL217 standards and has a white color, making it a sleek and reliable choice for home security. With an operating sound rating of 85 dB at 10 feet, this smoke alarm provides a clear and audible alert in case of a fire, ensuring the safety of you and your loved ones.