First off I think it is a great concept and the material quality is very good.However, upon putting the vest on it took 6 tries to get the zipper to actually work.Another concern that I have is the fit.
I have a 34 inch waste, and am 6' 185 lbs and the Large which is recommended is loose. Therefore, I don't believe I received the full benefit of the vest in my spin class and sauna.A medium with a better zipper may be all that I need.