Ideal raised the prices on the replacement flaps in late 2021. Check the whole door price here Ideal Ruff Weather pet door before you buy flaps. You may be better off getting the whole thing, particularly when orders over $100 ship free. These flaps need to be replaced every 5 years or so on average. The Ruff Weather doors come with 2 flaps, one in the inside frame, another on the outside frame. The flaps are sold individually. Ideal changed the way they listed the extra large flap size after a couple years of production. They originally called them 9 3/4 x 17, then later changed it to 10 ½ x 15, then went back to 9 3/4 x 17. The flap size never changed. If you have an extra large door, the extra large flap we sell will fit, regardless of what it says on the flap when you receive it.