CONVENIENT LOCK --- The knob switch is 4-way rotatable, you can easily rotate it to 4 positions with the arrow and icons to control your cat's access options: self, out, in and out only, fully blocked. ? IMPROVED BRUSH TRACK Weatherproof---Provides a fixed track with snap tabs for the weatherproof brush strip, securely attaching the brush strip. Even if the brush comes loose, it is easy to put it back into the fixed housing. This significantly helps the brush reduce noise, stop rain, wind or pests such as mosquitoes as much as possible. ? SCREW RISK --- Comes with 2 packs of 8 screws each, one with short screws and the other with long screws. Screw them on both sides to avoid breakage, not just on one side. You can make 8 screws for the 4 screw holes with long+long, long+short or short+short mounting, depending on the depth of the door/wall to be mounted. APPLICABLE FOR --- Inner dimensions 15*15.5. And the outer size is 19*5.5*22 It can be installed on interior doors, exterior doors, walls, windows, cabinets, glass, etc.