I really like these mittens, and I'm glad I bought them, but I'm giving them 4 rather than 5 stars because --- even though they're 2XL -- the thumb channel is cut too narrow to fit a liner. Any liner restricts circulation to the thumb, which defeats the purpose in the cold. But they're good to use as is, with just the built-in Thinsulate liner. They remind me of mittens an Indian woman made for me in northern Ontario in 1974. Those were made with smoke-tanned moose hide with sewn-in duffle cloth wool lining. I hope the sueded bison hide holds up as well as the home-tanned moose hide under field conditions.