6′ Semi-Coil Leash6 Semi Coil Leash 6 x 0. 31 (8mm) semi coil leash. Designed for knee or calf use. Double stainless steel swivels. The 6 Semi Coil leash provides a unique foil specific solution, where the coils avoid interference with the foil when paddling, and the straight segment prevents the coils from wrapping around your feet and toes when up and riding. The Velcro knee or calf connection keeps the leash up and out of the water when foiling, while the stainless