If you've been wishing you didn't have to continually open and close the screen door for your cat (or small dog), you'll be excited to know about the Pet Passage. It works in both standard hinged or sliding screen doors. The Pet Passage installs in minutes by simply cutting your screen to fit the frame, then snap-locking the frame together. This pet door is self-closing and lockable. The sloping hinge side means that gravity will close the flap without magnets. Since this pet door is supported only by screen on all four sides, we recommend that it be used for cats and less active, smaller dogs.