The SmartSound Dorgard Noise Filtering Door Holder is tailored for noisy environments, ensuring reliable fire safety. It operates like the original Dorgard but includes noise filtering technology which distinguishes fire alarms from background noise, guaranteeing prompt door closure during emergencies. With wireless installation and compatibility with fire doors, it's easy to integrate into existing systems.Features and Benefits Set up in minutes without wires Runs on standard C-size batteries, included in the price, lasting up to 36 months Automatically responds to fire alarms, enhanced by SmartSound Technology, unaffected by vacuum cleaner noise Fits any decor, available in Black or White, with an unobtrusive footprint Plunger grips floor firmly, with optional floor plate (MTL9490385B) for added grip on slippery surfaces or heavy doors Holds doors open at any angle, with a foot-operated release for convenience Compliant with fire safety regulations, failsafe mode ensures door closure