"The BRK Hard-Wired Smoke Alarms have been designed to install faster, perform better and be even smarter than before. Alarm has a large opening in the mounting bracket for easy access to wiring. Keyhole slots in the mounting bracket eliminate the need to remove the electrical box screws for installation. Battery installation and removal can occur while the unit is mounted to the ceiling or wall via the side load battery compartment. Connection to AC power is made with a ""Quick-Connect"" wiring ha"