Features: It is a fire smoke detector alarm, general purpose ideal for all areas : house, shop, hotel, restaurant, office building, school, bank, library, computer house and storehouse etc. Alert and warn people stay far away from danger field when it detected smoke. The detector adopts the special structure design and ASIC, has the dustproof, mothproof and anti outside light interference feature etc. Alarm test button Description: This smoke detector detects the smoke to make sure everyone is awakened and alerted in case of a fire emergency. The detector is suitable for detecting the smoke in home, room, shop, hotel, restaurant, office, school, bank, library, computer house, storehouse and etc. Easy to install and convenient to use. Photoelectric sensor for early detection from all directions. Specifications: Alarm volume: 10 feet to 85 dB Round Size: R = 102mm, H = 31mm Powered by 9V battery (Included) Usage: Fire, Smoke Is customized:no NOTE: The smoke alarm is less sensitive and requires a smoke maze to trigger the alarm. If testing is required, the test needs to be simulated in a closed, real smoke environment. Package included: 1/2/4/8 x Smoke Alarm  2/4/8/16 x Screws