Safe and Durable: The internal cat flap is made of ABS material, which is wear-resistant and durable. The edges are smooth and burr-free to protect your cat from scratches. Smooth design and paintable materials perfectly match the door and decor. Applicable Scene: The internal cat flap is suitable for all hollow doors, solid doors, and interior doors, perfect for laundry rooms, bedrooms, basements, etc. It will have its own activity space and your home will smell fresh. Barrier-Free Door Design: No one is home. Put cat food inside. With the internal cat flap, there's no need to worry about your dog getting in. The cat can come and go freely to play, eat and drink. No falling: The internal cat door is installed with screws, avoiding falls and gaps caused by the installation of the strips, no noise and no problems caused by door locks and damage caused by doors. External dimensions: 27 x 22.5 x 5.5 cm, through opening: 17.5 x 3.5 cm, suitable for doors with a thickness of 2 to 4.5 cm.