These are the calf and foot sleeves that improve circulation and enhance comfort when traveling. The sleeves have gradient compression that is gentle at the feet, firm on the ankles, and gentle on the calves, facilitating blood flow that’s restricted during long flights and preventing swelling. The sleeves help reduce lactic acid build-up to soothe tight leg muscles that may become sore during long periods of immobility. Made from 76% micro-nylon/24% lycra spandex, the thin sleeves can be worn comfortably under pants and they wick away moisture and are breathable to keep legs dry and cool. Black. Imported. Shoe sizes S (Men's 3-5 1/2; Women's 4-6 1/2), M (Men's 6-9 1/2; Women's 7-10 1/2), L (Men's 10-13; Women's 11+), XL (Men's 13 1/2+).