The patented automatic door bottom technology from Zero ensures an efficient seal against the floor or saddle. As the door is closed, the adjustable plunger is compressed against the door frame, activating a concealed flat spring mechanism. Zero door bottoms are designed to block penetration by air, sound, smoke, and flames.
AA = Anodized aluminum
Supplied with closed cell sponge neoprene
Consult your local AHJ for maximum allowable door undercut