I replaced the old flaps and security door with this conversion kit. The original dog door was installed over 15 years ago so it was time. Everything fit perfectly. I found it was easier to remove the dog door "frame" then try to install it while it was in place. Removing the frame portion only involved removing 4 screws and it slide out so was very easy. The flaps and security door fit perfect so we are ready for another 15 + years. We live in the mountains of Colorado so it get very cold - the double flaps work great keeping the cold air, snow and wind out. My only complaint was it took about 2 months and a couple of phone calls for the package to arrive.