Came quickly. In the case did not check yet, but checked with the help of a thermal imager. The heating zone is at the fingers, which is visible in the photo. Seems like it will work well.
I got these for my husband as he tends to walk around for his job. He says that overall, he feels good in his shoes. He likes to move his feet around with feet around with these insoles. Mainly for comfort and battling feet fatigue.