I have been looking for some top quality clothing for bow hunting this December and January. I came across Arctic Shield clothing and it is very warm but not bulky. It has what they call Retain technology which retains 97% of body heat. I got the H6 Series which has arm pit zippers to allow some air to circulate into the jacket if it gets too warm. I unzipped the zippers and warm air came flowing out so the Retain technology clearly works. The stuff is so warm that I DO NOT wear it walking in or out of the woods. Bibs and jacket in the H6 series run about $290 but it is well worth the $$$. I bought Under Armour Cold Gear last season and froze to death many mornings.