**CONVENIENT LOCK** --- The knob-style switch is a 4-way rotary control, allowing you to easily select from four modes using the arrow and icons to control your cat's access: in only, out only, in and out freely, or totally locked. **IMPROVED WEATHER-PROOF BRUSH STRIP** --- The design includes a fixed groove with snap tabs for the weather-proof brush strip, ensuring it is securely held in place. Even if the brush strip detaches, it can be easily reinserted into the groove. This feature significantly reduces noise and prevents rain, wind, and pests like mosquitoes from entering. **THOUGHTFUL SCREWS** --- The product includes two packs of eight screws each: one with short screws and the other with long screws. To prevent cracking, insert screws from both sides, rather than just one. You can use the screws in various combinations (long + long, long + short, or short + short) for the four screw holes, depending on the depth of the door or wall. **EASY TO INSTALL** --- The sales box includes a step-by-step installation manual and a video presentation for reference. Following the instructions and preparing the necessary tools makes installation easy. The tunnel depth can be adjusted to suit your installation needs. **APPLICABLE FOR** --- Inner size 2.17"