Made of ABS plastic, durable, resistant to scratching by your cat/small dog. Also, easy to clean and can be used for a long time 4 locking modes: open, closed, entry only or exit only, which allows your cat to enter and exit at will without you lose control of its comings and goings This Magnetic Pet Door is suitable for Windows, Glass Doors, Brick Walls, PVC, uPVC and Metal Doors With this Cat Flap cat you can control your pet's comings and goings and free your time to open the door without worrying about your pet. At the same time your pet will love a large and free home Prevents unwanted animals from entering your home Doors for the pet to install and use,allow the owner to 'pet to have a free pace of life We have two different sizes for your loving pets. no need to worry about the problem of walking through. This Magnetic Pet Door is suitable for Windows, Glass Doors, Brick Walls, PVC, uPVC and Metal Doors. Attention: 1.Some customers think that the door will be stuck and never fall off. Due to the low temperature which influences the function of the cat door. Please drip a drop of antifreeze engine oil which can solve this problem. Please don't worry there is no problem with the cat flap. 2. You must keep the glass door nearby before using the switches to change the model. 3. Please measure your pet's width before purchase. Specification: Material: ABS< /p> Size M: Outer Size: Hight: 20CM Width: 19CM Thickness: 5.5CM Inner Size: Hight: 16CM Width 15.7CM Weight: 0.34kg Suggested Weight: Weight 14KG Waist 40cm Size L: Outer Size: Hight: 25CM Width: 23.5CM Thickness: 5.5CM Inner Size: Hight: 19CM Width 18CM Weight: 0.52 kg Suggested Weight: Weight 16KG Waistline 60cm 4 Locking Positions can be chosen 1)Entry (possible entry) 2)Exit (possible exit) 3)Fully open (entry and exit possible) 4)Closed (entry and exit not possible) How to install < p> 1.To find a door and draw a square according to the size of the flap 2.To drill 4 holes in the four corners with an electric saw 3. To cut the square, and insert the flap of the cat into the hole (If the tunnel is thicker than your door, you can cut it according to your needs) 4.To screw the flap of the cat with a screwdriver.