3-flap system offers best protection from extreme heat & cold, drafts, insects, or driving rain. Energy efficiency is 3.5 times higher than single-flap pet doors. Snap-on weather cover for added insulation. Fits door thickness 1 1/2 x 2 . Dimensions - 10 5/8 x 15 1/8 . Flap opening - 8 1/8 x 11 3/4 . Great for pets up to 40 pounds. Durable plastic frame. MEDIUM WHITE