Serious swells call for a serious leash, the Kainui leash offers the security you need in double overhead to triple overhead surf. Constructed of the highest quality 5/16-inch (8mm) urethane Dura-Cord for maximum strength to keep you connected to your board in even the strongest surf. The Kainui is a continuation of Dakine's dedication since 1979 to making and refining surf leashes that protect both surfers and their boards in the most consequential conditions. 10' x 5/16'' (3.05m x 8mm). Material: Urethane, Stainless Steel.