ABURNUDREY Large Cat Flap4 Way Cat Flap Cat Flap with Tunnel Hide Cutout Cat Flap Dog Cat Door with Lock Cat Flaps for Small Animals Cat Mate Lockable Easy to Install White (L)With this cat flap you can control your pet's comings and goings and free up your time to open the door without worrying about your pet. At the same time your pet will love a big and free house+ product1. Trace the outline on the cardboardDraw the frame of the cat flap on cardboard and cut it out.Noticed:You'd better start by preparing these necessary tools: pencil, ruler, electric saw, drill, screwdriver, double-sided tape.2. Trace the outline on the doorUse a pencil drawing around the edge of the cut paper on the door you want to attach to.Noticed:Typically, the average installation height is about 10-15 cm from the ground.3. Cut a tunnel holeStart cutting the tunnel hole with a chainsaw.4. Put the cat door in the doorOnce the tunnel hole is cut, it is best to wrap it with a layer of wood skin. And if your hole is a little big, it is quite necessary.6. Reduce the depth of the tunnel if necessaryIf the cat door is too thick for your door, use scissors or a cutting machine to cut a part of the tunnel along line A or B. The cutting scale is about 2-4 CM.6. go up to the doorMount the cat door with double-sided tape on the door. 8 screws have been provided for your use, tighten them with a screwdriver on both sides.Noticed:screws for 4 holes on both sides, screw them all into 2 sides as above picture, please. These 8 screws are designed to work together, they are not short.Features1 X Large Cat Flap Door8 screws X8 x screw caps1 X Installation InstructionsIf the cat door is too thick, please use scissors or a cutting machine to cut along the line within the width of the frame.