Not sure why everyone had problems with the zipper but it could not if works better for me. It may be because when you put it on you have to squeeze your shoulder blades together and I did not have any problem at all. I used it to race in some really bad weather and used it underneath my wetsuit and not once was I ever called. And I was getting wet a lot on my jet ski with other Racers coming by but it did exactly what it was supposed to do.