PLEASE NOTE: Calf sleeve sizing is based on calf circumference. See size chart before ordering. The CW-X Compression Calf Sleeves are made with a seamless, compression variable four-way stretch fabric that offers improved circulation. Built-in webbing supports the calf muscles. Sanitized, antimicrobial and antibacterial properties. Sold in pairs. 90% nylon/10% polyurethane. Imported.