This Door Sweep stopper is adjustable from 32 to 36 inches to fit a variety of doors and windows and can cover gaps up to 1.5 inches. It is used under the door so that the outside cold air cannot enter the room and the inside heat will not escape, it will keep the room warm and cool. Also great for blocking dust, sand, light, and insects. Perfect for any type of door bottoms such as glass, wood, plastic, aluminum alloy, and bathroom doors. Using it under the door not only helps to block the door gap but also blocks the outside noise from entering the room. It will reduce outside noise by up to 4dB.