This small pet door made of quality ABS plastic, durable and sturdy sealing, designed for interior/exterior wood/metal doors, wall, cupboards, garage door, hollow core door, etc. Installation instrution provided. Built magnetic into the door flap can keep automatically closing when puppy cat go out or in. The knob-style switch is 4 way rotary, it is easy to rotate it to 4 modes with the arrow and icons to control your cat's access options: in & out freely, only go in, only go out or fully locking. Inner door flap edge covers sealing weather stripping, which eliminates noise from door closing, also keeps rain, wind, snow, fly from entering the home. Inside size: 7.1 x 7.3 inch/18*18.5CM, Outside frame size: 9.25 x 10.8 inch/23.5*27.5CM, Thickness: 2"/5CM. The door tunnel can be cut by scissor, saw or cutting machine by the depth/thickness of the doo or wall. Double-sided stickers can assist door installation.