I prefer this Collar "key" to the dog door to the other magnets that are covered in rubber (my dog destroys these) or glass, which are not as strong of a magnet, and also are attracted to other metal tags or connector rings and are more hidden from the electronic door lock. This key works more efficiently. Thanks.

great magnet-very small andworks perfectly-my puppy would yank the red tipped magnet off my older dog's collar-he cannot get to this one-yay!

A much improved product compared to the older rubber dipped magnets. Work great with magnetic door doors.

This is a great sturdy magnet for our dog door. Our dogs can go out anytime and it's wonderful.