Details Zoot Women's Compression Socks Size Chart Zoot has the edge when it comes to compression, delivering faster recovery and the solid stability you need for race day. This sock has been integrated with padded foot soles and achilles support for recovery comfort. These integration's help to effectively prevent foot irritations and injuries. The ZoneRx fabric helps to increase oxygen delivery to the leg muscles, preventing injury and soreness; while, the compressrx fabric improves blood circulation back to the heart. Both of these fabrics help to drastically reduce lactic acid build-up, the leading cause of cramps and soreness.