This is the waist leash for wing boarding. It is a highly adjustable way to connect the rider to the wing. Although this is an Ozone product, it is compatable with other brands like Cabrinha, F-One and Duotone. With the waist leash you also need to purchase a leash line, which comes in three different sizes: 2.3m, 3m and 4m, and 5m and 6m. Each size cooresponds to the size of the wing you are using.