You have to know that I wouldn't write about socks unless I had a good reason... These things are amazing. They have a double-layer which acts as a sock liner and absolutely prevents blisters because the inner layer sticks close to your skin while the outer layer moves with the boot. The two layers make the sock thick and comfortable all day. They have a ton of styles, but I've used the CoolMesh II for my summer hikes exclusively. I'll be buying their Merino Wool style for the colder months. I love these things.