Put on the spare PetSafe magnetic collar key 480 that unlocks the cat flap for your cat to give it a free pass to enter or leave the house even when the door is shut. The magnetic collar key will also help to keep stray cats outside. This PetSafe magnetic collar key was formerly known as Staywell magnetic collar key. It consists of 1 magnetic collar and 1 magnetic key and is compatible with the Staywell Deluxe 4-way magnetic cat flap (400 series) and Classic 4-way magnetic cat flap (900 series).