Putogesafe Smoke Detector, 10-Year Smoke Alarm with Photoelectric Sensor and Built-in 3V Lithum Battery, Fire Alarm with Test Button and Low Battery Warning, Fire Safety for Home, 4 Pack

【Long Battery Life-10 Years】This smoke detectors equipped with 10-year 3V lithium battery for continuous power supply, which can reduces the trouble of frequent battery replacement, protecting your home for a decade and energy saving.
【Advanced Photoelectric Technology】This smoke detector battery operated adopts industry leading photoelectric sensor technology, which is optimized to detect slow burning fire quickly and accurately, provides the earliest possible warning of fire to helps your family keep far away from fire dangerous.
【Self-Check Function】This smoke alarms equipped with a big test/silence button, in case of non-emergency smoke (e.g those caused by cooking or steam), you can touch it with a stick for test weekly or turn off the annoying false alarm sound, besides, the sound of test mode is low, which can avoid to frightened your baby with lound sound