Sound-activated, wireless fire door holder automatically releases when the fire alarm sounds, preventing the spread of smoke and fire. IntegralDual Modeuses 'listen and learn' technology to learn the sound of a fire alarm which helps prevent false activation, this feature also means the device can be fitted to hold the door straight out of the box. Ideally suited to environments where it is essential to have doors in an open position at certain times of the day to aid access, but equally as important to ensure the doors are closed in the event of a fire. Easy to install, hygienically and discreetly at the top of the door. Device is fitted to the wall. Features include LED display, manual release button and a low battery warning display. Perfect for areas with uneven floor surface. Mounted at the top of the door to protect from damage. Advanced Acoustic Digital Technology Battery-Powered Holding Force: 200N Programmable Timer Low Battery Indicator Digital Display 1 Year Guarantee...