I’ve installed 5 or 6 dog doors over the past 15 years and this is by far the best one. Steel frame instead of plastic makes it stronger & tougher. The dual flap design creates an air buffer zone and does a great job of keeping the cold out. The flaps seal tightly when closed, on a windy day I couldn’t feel even a whisper of air coming through. Install was easy enough, cut the holes inside and out and place it in. The template provided for the cutout was too big in my opinion (about 1-1/2″ too wide) I think they made it big on purpose to give more wiggle room for people that make less than perfect cuts. I just traced around the frame for my inside cutout hole. Made for a snugger fit. Great door, dogs love it and have no problem going thru 2 flaps.