This surface mounted high quality automatic door bottom is specifically designed to create the best sound seal possible for normal sound levels. Anodized aluminum finish and fits doors 36".. Built to last, our door bottoms have been tested through 5 million cycles! Features a high quality closed cell sponge neoprene rubber seal. Maximum drop of 1" which is activated upon closing and opening of the door to ensure smooth usage (no batteries or electricity required). This ADB can be surface mounted to a right or left handed door.