Made to zip over your shoes and calves, the wind tunnel-refined booties are composed from silicone-coated stretch fabric over the shoe, primed to smooth the airflow, and engineered grooved Lycra® on the ankle that detaches the air altogether.Held in place as you race by flat polyurethane tape at the top, these booties wont let you down and could make the difference between victory and defeat.Key features:Proven in the wind tunnel to save 6w at 45kmph over a normal sockMade with silicone-coated stretch fabric over the shoeWith grooved Lycra® on the anklePolyurethane tape at the top keeps shoe covers in placeSecured with a YKK® zipper