Amazon.com The BRK hardwire heat alarm is ideal for use in attached garages and other locations where standard smoke alarms are not suitable. The unit alarms if either the temperature reaches 135 degrees Fahrenheit or the temperature rises more than 15 degrees Fahrenheit in one minute. The HD6135FB hardwire heat alarm includes these features: 120-volt AC/DC with 9-volt battery backup 135 degrees Fahrenheit fixed rate and rate-of-rise temperature sensing Microprocessor controlled for fewer nuisance alarms The test/silence button both silences a non-threatening alarm or low battery warning and allows you to test the unit's functionality. Silencing and testing functions can be run by most household remote controls such as the ones used for the television, stereo, and VHS or DVD players. Latching alarm indicator which automatically identifies which unit initiated the alarm. 120-volt AC inter-connectable (with maximum 18 compatible devices). The alarm can be interconnected with up to 12 other compatible smoke alarms and six compatible devices like bells, horns, repeaters and door closers. If one unit triggers an alarm, all smoke alarms in the series will sound. Power indicators show which unit in the series initiated the alarm. 85-decibel horn. Meets UL requirements. 10-year limited warranty. --Bree Norlander What's in the Box One heat alarm, one 9-volt battery, and user's manual Product Description The First Alert HD6135FB Hardwired Heat Alarm with Battery Backup enhances your home's fire safety by accurately detecting high temperatures and rapidly rising temperatures. Easy to install on a wall or ceiling, this heat detector is ideal for use in crawl spaces, laundry rooms, garages, kitchens, and other areas where smoke alarms aren't an option. It comes equipped with advanced rate-of-rise sensing technology and a microprocessor that dramatically reduces the number of false alarms. If the temperature reaches 135 degrees Fahrenheit or rises more than 15 degrees Fahrenheit in one minute, the alarm alerts you to the danger with a loud 85-decibel siren. Designed to be wired directly into your home's electrical system, this 120-volt AC hardwired temperature sensor features a 9-volt backup battery that helps keep the alarm functioning even in the event of a power outage. An intuitive mounting bracket makes installation hassle-free, while an easy-to-access battery drawer allows you to quickly change the battery. The alarm can be configured to work with almost any standard household remote control (sold separately), so you can remotely silence nuisance alarms with the push of a button. And thanks to the convenient test/silence button, it is easy to check alarm function and mute false alarms. This heat alarm can integrate with up to 12 other First Alert or BRK hardwired alarms and up to 6 other compatible devices. It features a latching indicator that identifies which unit triggered the alarm.