Package Includes:1 * Smoke AlarmAlarm volume: 10 feet to 85 dBRound Size: R = 102mm/4.02" H = 31mm/1.22"Powered by 9V battery (Not Included)Features: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 buttonEasy to install Photoelectric sensor for early detection from all directions.