Attach the PetSafe 480 replacement collar magnet to your cat's collar, allowing them to unlock the cat flap and enter or exit your home freely, even with the door closed. The magnetic collar key helps keep stray cats outside and grants access to your home only to the wearer of this cat collar. This magnetic collar from PetSafe was previously known as the Staywell Magnet Key. It consists of a cat collar and a magnet key and is compatible with the Staywell Deluxe 4-Way Magnetic Cat Flaps (400 Series) and Staywell Classic (900 Series). Color: Black; Material: Plastic; Dimensions: 14 x 1.9 x 0.4 cm (L x W x H); Compatible with: Staywell Deluxe 4-Way Magnetic Cat Flap (400 Series); Staywell Classic 4-Way Magnetic Cat Flap (900 Series).