The HO Sports Proton Kneeboard is a one-size-fits-all kneeboard featuring a Powerlock single locking knee strap for maximum comfort and ease. It?s surf inspired shape and deep tracking channels make wake cuts and landing super smooth. The retractable fin system allows for aggressive control with fins up, or easy surface turns and hydro sliding with fins down. The easy up hook makes deep water starts a breeze for all rider skill levels.