Perfect Pet Pet Door with Telescoping Frame, Super Large, 15" x 20" Flap Size

Inner telescoping frame that adapts to doors of 1 ¼-inch to 1 ¾-inch thickness | Impact-resistant super-strong thermoplastic; Clear flap allows pet to see if slide is in place | Tamper Proof Mounting System, door cannot be removed from outside | Simple 4-step installation (Average install time: 20 minutes) | Flap Size 15" x 20"