Double-flap system insulates for energy efficiency. Aluminum frame with durable plastic telescoping tunnel. Can be installed in interior or exterior walls or doors 4-3/4" to 7-1/4" thick, including siding, stucco, and even brick. Add an extension tunnelfor deeper walls. Features 2 flaps, one in the inner frame and one in the outer frame.null
LARGE FOR UP TO 100 LB. DOGS
Frame Dim: 14-1/4 x 21-1/16" � Cut Out: 11-7/16 x 18-1/8"