“This product ran large per sizing chart specs. It said my waist would be two inches too large for the largest spec of a medium size. My waist would be too small if I was wearing a couple inch thick chunky sweater. Also, Idk if I just couldn't tell from the pic but this is a full on ski coat with fleece lined sleeve cuffs and everything. Definitely no type of under layer. But thats great! Its almost the same price as the other options and a whole coat! Just not what I was looking for. Am returning for a vest. Cannot speak to heating effectiveness as I didn't use it.”