Petmate Indigo-ovi

The vinyl flap is thick enough that it doesn't flap around in the wind, and it snaps shut tight to keep the cold draft out. My dog pushes right through it without any trouble, and it took me about two minutes to pop in place.

I was skeptical the door would line up right, but it clicked into the frame on the first try and keeps the drafts out of the Indigo house completely. The flap swings shut smoothly even after a week of the dogs barreling through it.

The door snaps into place easily and seals well enough that the interior stays noticeably drier during a heavy downpour. Took a bit of fiddling to align it perfectly the first time, but once it's on, it's secure.