I bought these for my husband who works outside all winter. He really likes the Duofold brand so I ordered him a few new pairs. I normally order the mid weight but decided to try one pair of the heavy since it gets so cold here. I got the mid and heavy the same day and once I took them out of the package I couldn't tell which one was heavy. There is hardly a difference between them other then the price. I think I will stick with the mid from now on.