[Interconnected Smoke Alarm] The wireless battery-operated interconnected smoke alarms can interconnect with each other, One goes all go wireless interconnected smoke alarms so that they all sound when one is activated, keeping you and your family safe.Up to 20~50 compatible interconnected smoke alarms can communicate with each other and alert you when there is a problem across the house even in a different room or on a different floor. Wide Coverage of 20-40m² [non-removable 10-year battery & Photoelectric Sensor] Interconnected Smoke alarm provides 10 years of continuous power with a built-in lithium battery, saving on energy while ensuring the alarm is always on, no need to change the battery constantly. Photoelectric sensor alarm detects the large particles typical of smoky, smouldering fires while reducing the number of false alarm [Easy Installation] Smoke detector comes with screws and mounting brackets, easy to install in several minutes since there are no wires needed. Applicable to housing, company, factory, hospital, hotels, warehouse, office, shopping mall, schools (do not use in bathroom, laundry room, kitchen) finished attics and basements [Loud 85dB Sound & Hush Button] Battery-powered interconnected smoke alarm features a loud 85-decibel sound alarm that can wake even the soundest of sleepers and alert you where the danger is located. A one-touch hush button enables to silence false alarms and allows you to test the unit monthly, which is more convenient than disabling the unit [Certified Quality] This wireless interconnected smoke alarm is made of ABS, which is very durable and resists high temperatures, doesn’t contain any radioactive material, in full compliance with AS3786