SITERWELL Smoke Detector, 10 Year Product Life Fire Alarm with Magnetic Fastening Kit, Smoke Alarm with Photoelectric Sensor and Low Battery Warning Function for House, ETL-9th Listed, GS509A, 10 PackBrand: SITERWELL Features: 10 Year Product LifeThe smoke detector has 1 year 9V battery. This smoke alarm can be used for ten years with continuous battery replacement. Working smoke detector cut the risk of dying in a home fire by 50% while a home fire starts every 83 seconds! The faster you realize a fire warning, the more time to escape from the fire Photoelectric TechnologyThe GS509A is a photoelectric smoke alarm. The photoelectric technology, it