The Shuttle fire door retainer
Automatically releases your fire door when the fire alarm sounds.
Is wireless door retainer,which works acoustically and holds a door open,legally.Which is very easy to install.In minutes and operates when your fire alarm goes off,and releases the doors ,to keep any fire compartmentalized.
All door retainers come with a 5 year money back guarantee.
The Shuttle 501 with LCD screen is very easy to install,and distinguish between any other noise.and can be installed on any door. a kitchen where the noise maybe relatively high.As also where music could be very high.The Shuttle can simply distinguish between any background noise.
The dorgard 1326 and smart sound acoustic door holder.,take C size batteries.