The BRK FG250B dual ionization smoke detector is designed to detect the small particles produced by fast, flaming fires and is battery operated by the included 9 volt carbon zinc battery. The alarm is listed to UL 217 standards and features a tamper resistant locking pin that prevents the removal of the battery, making it ideal for apartments, dormitories, and hotels. A single button both silences false alarms and allows the user to test the alarm with ease. Operating in temperatures from 40 to 100 degrees Fahrenheit and in humidity up 95%, this alarm has an 85-decibel alarm.