Mid-Calf Aero Socks Designed for High Speed Racing Redefine your race day kit with the S-PHYRE FLASH technical racing socks. The rubber-infused upper and knit aerodynamic ribs are designed to save precious energy at high speeds. Arch and heel supports help secure feet for stable pedaling while breathable mesh on the instep keeps feet dry. Knit aerodynamic ribs save precious seconds. Breathable mesh instep helps vent heat from the shoe. Arch and heel supports secure feet for stable pedaling. Durable, reinforced ribbing for long-lasting heel stability. Made with certified 72% recycled polyester. 56% Recycled polyester, 38% Polyester, 4% Elastane, 2% Polyamide Size Chart Shimano Socks Size Chart