Convenient Locking---The knob-type switch is 4-way rotation, you can use arrows and icons to easily rotate it to 4 modes to control your cat's access options: in only, out only, free in and out, fully locked. Improved Weatherproof Wiper Strip---It provides a retaining groove with a snap for the weatherproof wiper strip, securely holding the wiper strip. Even if the brush strip comes off, it can be easily put back into its retaining groove. This greatly helps the brush strips reduce noise and provide maximum protection against raindrops, wind or pests such as mosquitoes. Thoughtful screws --- Comes with 2 packs, each pack contains 8 screws, one pack is short screws and the other pack is long screws. Please screw in from both sides, not just from one side to avoid accidental breakage. You can make 8 long+long, long+short, or short+short sets for the 4 screw holes, depending on the depth of the door/wall you want to install. Easy to install --- The instruction manual and step-by-step installation instructions in the installation demonstration video included in the sales box are for your reference, please pay attention and prepare the necessary tools for easy installation according to your needs. Tunnel depth can be reduced based on your installation needs. Fits --- Internal dimensions 2.17"/5.5cm (D) x 6.18"/15.7cm (W) x 6.30"/16cm (H), suitable for cats with a waist shorter than 15.75"/40cm. External dimensions are 2.17"/5.5cm (D) x 7.56"/19cm (W) x 8.46"/21.5cm (H). Suitable for installation to interior doors, exterior doors, walls, windows, cabinets, glass, ETC.