Aico 180 Optical Smoke Alarm runs on a 12V to 24V DC power and has a 9V Alkaline battery back-up. The alarm gives a fire warning when adequate smoke enters the chamber. The alarm is supplied with an Easi-fit base that allows quick and simple installation of the smoke alarm head. The Easi-fit base automatically connects both the mains power and battery as the alarm slides on. The alarm has a pair of built-in Volt free relay contacts i.e. can be used to switch into a burglar panel via hard-wired interconnection. The Optical Smoke Alarm has other advanced features such as built-in circuitry to aid suppression of voltage transients and RF interference to further reduce the chances of false alarms under such conditions.