I'll put in a vote for the warmbag. Similar to the heater body suit, but different.
I hunted last weekend here in NH, was 15 degrees and 30 MPH winds. I grabbed my wife's warmbag, but FORGOT my third sweat shirt and insulated overalls. Effectively I was dressed comfy for down to about 40 degrees. I then jumped into the warm bag and put on a fleece balacava for my head, neck and face. I sat for 3.5 hours and was not only not cold, I was actually toasty warm. I was doubting the weather forcast, until I got up to leave that is and took off the warm bag. By the time I packed up at the stand site and walked 15 minutes to the truck I was FROZEN solid.
Differences from WarmBag over HBS that I like:
- You can wear it and walk, you can unzip the bottom and stick your legs out and walk. This is what my wife does at the end of the hunt.
- You can unzip the sides and stick your arms out (HBS you have to drop it off your shoulders.
- It bundles up smaller for easier carrying.
I was VERY impressed with this thing. At 30 degrees you could go in with your normal hunting clothes, skip most of the layers and all the heavy duty cold gear and jump inside this. It traps your body heat and keeps you warm.
My wife has also used this watching our kids play soccer into November, COLD Saturday mornings, heck cold early spring mornings while all other soccer Mom's froze, she was fine!
Get it, you'll love it.