CONVENIENT LOCKING --- Knob style knob is rotatable in 4 directions. You can easily rotate it in 4 modes with the arrow and icons to control your cat's access options: entry only, exit only, free entry and exit, totally locked. BRUSH STRIP WEATHER RESISTANT WATERPROOF --- It offers a fixed groove with snap tabs for a weather resistant brush strip. Even if the brush strip comes off, it is easy to put it back in the fixed groove. This greatly helps the brush strip to reduce noise, keep out raindrops, wind, or pests like mosquitoes. , one is filled with short screws, the other is long. Screw them with both sides to avoid cracking, don't just one side. You can make 8 screws for the 4 screw holes with long+long, long+short or short+short groups depending on the depth of the door/wall being installed. EASY TO INSTALL --- Step-by-step installation instructions in the installation manual included in the sales box and in the installation overview video. The tunnel depth can be reduced depending on your facility needs. APPLICABLE FOR --- Inner size (L x W x H) 18 x 19.5 x 5.5cm, it is suitable for cats whose circumference height is less than 60 cm. And the outer size is (L x W x H) 23 x 27 x 5.5cm. It is suitable to be installed on interior doors, exterior doors, walls, windows, closets, glass, etc.