We have been working for sometime on a period correct machine knit sock. This one is closer, but we are still working toward the goal of a 100% correct cotton machine knit socks. It's quite honestly never been done, and is extremely difficult with modern looms and techniques. NONE of the machine knit socks, even those offered by "authentic vendors" are correct....NONE. The heel on all of them, including these we are currently offering, are a modern type heel. Period machine knit socks had to be cut and sewn because the heel was knit as a flap and then sewn to the body of the sock, giving it a "flap" look. However, we wanted to help fill the void by offering a "best quality available right now" type machine knit cotton sock while we are continuing toward the goal of a 100% authentic machine knit cotton sock. Ours are knit from 100% cotton, with a softer hand than many reproductions. Our cuff also has a small amount of cotton elastic knit in to help the socks stay up on your leg and make them have the more defined shape like the socks in the Clara Barton collection. They do stretch, so are being offered in one size fits most.