Osom makes socks from thread made mostly of recycled clothing and no chemical dyes. I think their real aim is to sell the thread to other clothing makers, and the socks are sort of a proof of concept. They can get a little pilly with use, but shoes will cover that, so it's not a big issue. All their socks are "one size fits all", but the thicker "Outdoor Essentials" style is a little smaller than the "Classic" one.

The socks' color reflects their high denim content. If you look closely, you can see little fibers of all different colors from whatever other clothing was brought in to re-use.