UNION DoorSense is a standalone unit which can be fixed to a fire door in seconds to provide a reliable way to keep it open but will automatically release if the fire alarm sounds. DoorSense is incredibly easy to install, needing no wiring or special skills, it can even use the same footprint as some older units. Once fitted, DoorSense is powered by two Alkaline C batteries for long working life, and has a low battery indicator to help you keep the unit in excellent working order. Once in place you can have it working manually or automatically via a timer to set a night release time. DoorSense is available in three colours black, red or white, and comes supplied with full fitting and setup instructions along with batteries for instant start up. Suitable for use with fire rated doors using door closers with a power rating between 3-7. Compliant with BS EN 1155. EMC Tested and rated for timber doors (FD120) 1 x UNION DoorSense Acoustic Release Device - White