The Acorn original! This famous slipper sock has been comforting the feet of astronauts since 1982. Ragg wool uppers of 85% wool, 13% nylon, and 2% spandex. Cotton twist uppers of 93% hypoallergenic cotton and 7% spandex. These slipper socks feature a lofty Acorn memory-foam midsole over a comfort cushion layer of featherweight EVA. In addition to comfort, the full-grain leather sidewall and suede leather outsoles offer durability.