I've tried a lot of different stuff but I do like wearing Minus33 heavy weight base with fleece as the next layer then the the big dog coveralls from Cabelas which are heavy and windproof. I usually camp out and hunt most of the day in one of my favorite spots (gun and bow. I have found the Body Heater Suit works ok, but I just started using the base of Minus 33 and the fleece and that really makes a big difference. Got the Minus33 stuff from Amazon and I had some fleece.