1PROFESSIONAL DESIGN: Screen cat door is designed for all breeds of dogs, cats, pet pigs, etc. allowing them to move freely in both indoor and outdoor spaces. 2LOCKABLE: Cut off the two pull tabs at the top and lock one into a slot on one side to ensure your pet is safe and passes through the door with your awareness.Double sided slots are lockable. 3STURDY AND DURABLE: The Inside door flap is made of ABS, which is sturdy and durable to withstand daily use and will not be damaged by scratching or rough play. 4EASY INSTALLATION: Use a slot screwdriver to install the door separately, the inside door flap does not come with a screen insert, you need to place this door on top of an existing screen door, then cut the screen against frame and place it into the flap. 5APPLICATION: Pet screen door is only suitable for screen doors or window or thin exterior doors, not for thick aluminum or glass doors. 1 xPetScreenDoor 1 xUser Manual