FireAngle Smoke Alarm is a mains powered smoke alarm with high performance optical sensor, 9V battery back-up and improved Push-Fit base for quicker and easier installations; designed to ensure quick and easy installation of base unit to the mains feed supply at installation stage (1st fix) and for quicker and easier connection of alarm to base unit (2nd fix). Optical technology reduces nuisance alarms, suitable for use in areas adjacent to where cooking fumes are present.