If your zipper works fully, you're way ahead of me. I cracked the original rear window in my BestTop while undoing it one very cold winter morning. The replacement window ($100 IIRC) from BestTop zipped in just fine... but when I went to unzip it a couple of days later, it would only unzip 80% of the way before getting bound up to the point that me holding the rear bumper with my left hand and pulling down as hard as I can with my right hand is just enough to unzip it extremely slowly. And the part of the zipper that gets bound up does not stay zipped on its own; the first 4-5" of it are flared open. The zipper on the replacement window looks fine... but it doesn't look to be exactly the same as the one on my top; the 'teeth' look slightly taller. Since they are from the same company, my only guess is that they started using a different zipper at some point (my top is almost as old as the truck itself). I've just made it a point not to unzip my top anymore than necessary the past couple of years <img src="/forums/images/graemlins/notooth.gif" alt="" />