In case you are wondering, I have used the Arctic Shield boot blankets for 20 years. They are light, pack down small too. Coldest temps I used them in was in the North Maine woods whitetail hunting. Temps were -9 to about +10 for highs.We saw nothing. Everyone we talked to also saw nothing. It was a late rutt so they were way up there and it was decently warm during the day. I wore my uninsulated boots but was glad I had my insulated ones too
The pop a hand warmer in on top of your boots is what I do in stand. The larger body warmers do work better than a small hand warmer. Buy BIGGER than your boot size. They are a snug fit.