Oceanus Retractable Reel Board Leash
If you are going to use a board leash this is the only choice! The Reel Leash® has a lightweight plastic housing which contains a stainless steel spring and spool of webbing with a brass snap hook.
Safer than traditional tubular leashes, because when separated from the board, the board will safely fall away from the kiter. This releases the webbing out 10′, with enough torque from the spring system to control and eliminate slack. This will reduce the risk of the board sling shooting back.