Size M: Outside size: 19 x 20 x 5.5 CM (W x HXT); Inside size: 14.5 x 15.5CM (W x H); Cutout size: 16 x 17 CM (W x H); Fit cats up to 16lbs, Suitable for any wall or door up to 50mm thick; Cat Door: A great solution to give your cat access to any interior space while giving you complete control. Perfect for accessing the bedroom or even access to the food or litter box when kept behind closed doors to keep dog and kids away. Simple and good design: the transparent flap lets the pet see through the door. The outer screen is waterproof. The brush strip reduces the noise when closing the door. Easy Installation: Complete instructions provide easy installation in windows, doors, closets, etc.4 switching modes: switches only turn off, only on, both on and off, and fully locked, easy control of your pet getting in and outPet Door Interior Cat Doors gives your pet convenient access to food, water or the litter box behind closed doors. With this cat flap, your cat will be satisfied and love the freedom that the cat door offers. The brush strip can reduce energy loss and silent actions without disturbing the voice. The cat will not be afraid if wind or snow is trapped outside, waterproof and tight. You will be freer at home! 4 types of closureFly screen dog flap with to allow cats to come and go as they please, or to keep them safe in the house or away when needed. The locking options include: open in, open out, open both ways, locked. Quiet This cat flap inner door is extremely quiet and offers optimal protection against drafts with a special seal and a magnetic lock. with brush strip for low-noise entry and exit. Suitable for most cats and dogs.