Give pets the convenience of easy entry and exit with CRL Deluxe Pet Doors. They are available in three sizes to accommodate all pets – from small kittens to large dogs. All feature a tough, flexible rubber flap with permanent magnets to keep them closed when not in use. The sturdy extruded aluminum frame has an anodized finish to resist corrosion. A rigid hardboard security panel slips into guides inside or outside to keep pets from using the door. Pet Doors can be installed in walls or doors with a minimum thickness of 1/4" (6 mm), and are supplied with all necessary fasteners.