One size fits most. These fun socks are perfect for yoga class, pilates or dance class. They are heel-less and toe-less to prevent you from slipping but still keep you warm. They are knitted in fun colors of black, pink,orange and purple. Or you can wear them with your flip flops when you are not ready to give them up or getting your toes done.Or are great for just lounging around the house. Color variations will occur with self-striping yarn. They are knitted with a 75% wool and 25% Nylon mix, can be washed in the machine, lay flat to dry.