Bought for hunting this year. I liked what I read about this product. took it off and it worked fine but i think it works better if you wear less. I did it in 3.5 hours at 25 to 33 degrees. but I think I had too much underneath so it might affect the efficiency of the heat recovery system. The reason is that I took it the following weekend, just messing around with a long sleeve t-shirt in my 40's and quite warm, just getting up and making slight movements. The only issue with the jacket is that I wish it had an extra drawstring to adjust it a bit and maybe a few more pockets, but that doesn't matter as I carry the bag with me. overall a good jacket