DESC: PetSafe Ultimate Pet Door has a rustproof, strong aluminum mitered frame with a decorator baked-enamel finish. It has a unique double flap system - outside flap acts as weather stripping for a complete energy seal. The door is self-framing in doors from 1 1/4" to 1 3/4" and may also be installed in a wall (additional framing required). The latching closing cover may be inserted on either side of the door. Flap opening: 8" x 11 1/2"; for pets up to 40 lbs. Shipping weight: 10 lbs.