I received the insoles in December and was super excited to try them out on some cold hunts. The first time I took them out it was 34 degrees. I wore a pair or thermal socks and used the insoles and my feet stayed plenty warm. The next two occasions I used them was in 15 degree or lower temps. I was wearing 400-gram boots and somewhat thin socks as recommended in the instructions. My feet froze. I don't believe these are made for temperatures much below freezing unless you have heavy boots.
The insoles were built well and held up throughout the many times I used them them with no issues. They are very easy to use, recharge, and put back to use. I do wish the battery lasted longer, but understand that only so much power can be stored under me feet without sacrificing comfort. Once I added them to my boots I didn’t notice any difference in boot comfort. You do have to do a little cutting to make them fit your boot correctly, but it isn’t a tough task.
Given my experience with the insoles and considering the cost ($130), I wouldn’t recommend them at this point in time. I know plenty of people that swear by them, but I didn’t share that experience. I will give them another shot this fall/winter as the temperature drops and give ya’ll an update.