Compression socks that target plantar fasciitis, bone spurs, Achilles tendonitis, inflammation and general foot pain. Size M supposedly fits a man's US shoe size 6-9 and a woman's US shoe size 7-10.5. However, I wear a 10.5B and they are too tight for me. Each pair sells for $13 a pair, in a 4 pack $23.75. Machine wash and dry flat. Do not use fabric softener.