The Staywell 300 Series 4-Way Locking Cat Flap is designed to be mounted in doors or walls (When used with the optional 2" tunnel extensions). The Staywell 300 comes with a removable 2" tunnel extension, this way the Cat Flap can be used for very thin applications as well. The 4-way locking feature allows you to control the access of your cat by manually setting the locking mechanism in 4 different modes. The flap is rigid plastic with a magnetic strip along the bottom to hold flap in closed position. The Staywell 300 Series has a 3-year manufacturer warranty.