Give your cat the freedom to come and go as it pleases with this cat flap featuring a 4-way locking system. Slide locks on the bottom of the flap to set the door to one of the following options: The cat can only enter from the outside but cannot come out The cat can exit but cannot enter (to prevent other cats from entering too) The flap is locked on both sides The flap is completely open and the cat can come and go at will The cat flap is easy to install and is suitable for any wall or door up to 50mm thick. Also suitable for small dogs/cats. Features: Size: S19*19.7*2cm M19*19.7* 5.3cm L25*23.5*5.3cm XL:25*5.5*27.7cm(please measure your pet before ordering!) The 4-way cat flap is brand new and boxed Material: hard plastic Installation method: Tools needed: electric drill , iron saw or electric saw, measuring ruler; Step 1: First use a piece of paper to draw the size of the door cover (there may be a few millimeters error) ; Step 2: Finish the drawing and mark it on the door and draw the seal with a pencil; Step 3: Use a drill to drill a hole in the four corners of the painted door, then start digging the hole directly if there is a chainsaw; Step 4: If it is a glass door, use a glass scribing tool to gently pry it open and secure it with glass glue. Step 5: The hole is cleaned, now first get a layer of wooden leather to wrap around the hole, for the sake of beauty; Step 6: Install the cat flap, there are accessory screws and screw- them with a screwdriver; Step 7: The screw port is also equipped with a screw cover, press it, OK, finished! Package included: 1 x flip-up pet door< /p> getveryrich Note: The data is all manually measured, please allow 1-3cm error, due to the difference in light and display, there will be a certain color difference , the actual object received shall prevail.