4 Way Locking Cat Flap for Cats and Small Dogs with a circumference of 40cmcat flap (20x19x5.5cm)With this Sailnovo Cat Flap, your cat will be very happy and will soon enjoy the freedom that the cat flap offers. The brush bar helps reduce noise, it is very quiet, there is no sound to hear, the cat can freely enter the house and you will also have more freedom at home!MExternal dimensions: 19 x 20cm (WxH), passage dimensions: 16 x 15.7cm (WxH), depth: 5.5cm.+ product1. Draw the outline on the cardboardDraw the frame of the cat flapPlace on cardboard and cut out.2. Draw the outline on the glass doorPencil drawing on a cutting edge on a glass door3. Drill 4 corners for the holeFirst drill the 4 corners with an electric drill4. Dig a tunnelFirst, you'd better drill holes in the corners of the outline. To do this, you'll need to cut out the entire block of tunnel holes with a saw.5. Drill holes for the screwsInstall the cat flap on the door with double-sided adhesive tape. 4 screws are provided for your use, tighten them on one side with a screwdriver, suitable for glass doors.6. Installation is completeNote: Please consider the height of the glass/window/door where you are installing the cat flap, usually 10-15 cm from the floor. If it is too high, your cat will not be able to jump out of the cat flap.4 locking positions can be selected1. Enter (can enter)2. Leave (can exit)3. Fully open (can enter and exit)4. Close (no entry or exit)Features1. Some customers think the door will be stuck and never open. The function of the cat flap is affected by low temperature. Please drop a drop of antifreeze oil to solve this problem, don't worry about the cat flap without problem.2. The glass door must be kept closed before using the switch to change the model.3. Please measure your pet's width before purchasing. This magnetic cat flap is suitable for windows, glass doors, brick walls, PVC, uPVC and metal doors.