The Staywell Manual 4 Way Locking Classic Cat Flap with Tunnel is so easy for your cat to use. It features 4 locking options to enable you to decide whether you would like your cat to stay inside only outside only give them the option to come and go as they please or keep them firmly put with the locked option. This design is suitable for cats up to 7kg and is simple to install featuring a tunnel that can be cut depending on the width of your door. This product can be fitted in the following places:  Wooden doors Glass windows & doors single & doubled glazed (consult a glazier as it is not possible to cut holes in toughened glass or double glazed units except at the time of manufacture) Brick walls PVC/uPVC/Metal Patio/ Sliding doorsThere are many advantages to fitting a cat flap door into your door. It gives you the freedom to come and go as you please without having to worry about letting your cat in and out of the house during the time when you are not there. It gives your pet the opportunity to capture some fresh air and exercise and go to the toilet outside that saves time and money on expensive litter. This freedom means that the relationship between cat and owner is improved. Don’t worry about training your pet to use the new door simply be patient and allow your pet to discover for themselves that they can go through the door. Give them a reason to use the door for example food they will soon become accustomed to using this useful product.  Manufacturer 3 year warranty Overall Size: 22.4 x 22.4cm Cut Out Size: 16.9 x 16.9cm Tunel depth: 6.5cm Glass Cut Out: 21cm diameter circle Maximum Pet Shoulder Width: 16.cm Maximum Pet Weight: 7kg - cats Model 917EF (was 917EFS)