PetSafe® Big Cat 4Way Locking Cat Flap - Easy Install Hardware Kit Included. Grant your pets the independence they deserve with the PetSafe® Big Cat 4-Way Locking Cat Flap, specifically sized for large cats and small dogs up to 22 lbs. This versatile door features an exterior size of 11-1/2" x 11-1/2" and accommodates pets with a maximum shoulder width of 7-1/2". The primary benefit is complete control over access, thanks to its easy-to-use 4-way locking system (In Only, Out Only, Opened, or Locked), ensuring safety and security. Designed for universal fitting in wooden doors, glass windows, brick walls, and PVC/UPVC, this flap includes an easy-install hardware kit and an optional tunnel extension for thicker doors, allowing you to quickly and easily create seamless access anywhere in your home.