The Magnetic 4-Way Locking Cat Flap gives you cat a key to the house. The 4-Way lock allows you to choose from four access options: open, locked, in-only and out-only. The open option allows entry or exit, the locked option does not allow entry or exit, the in-only option allows entry but no exit and the out-only option allows exit but no entry. When the flap is not locked, only your cat's magnetic collar key will open the flap.  The 4-Way Locking Cat Flap can be installed in interior or exterior doors or walls. An optional tunnel is included for installation in doors and walls 5 cm (2") thick. Additional tunnels are available (sold separately) for installation in doors and walls thicker than 5 cm (2").