Our “Performance Rear Sponson” kit is designed to improve the riders confidence when riding their Stand up watercraft. The design was created by Chris Hagest. He says: These Performance Rear Sponsons offer improved turning grip, better stability in a straight line and when leaning over in a turn. The difference between us and the other options on the market is grip and high speed turning the ski is easier to lean which makes the ride smoother through the complete turn. The HFC sponson bolts to the inside of the bond flange and it comes with two hardware options: stock bumper (PW-SP-215) that bolts through the OEM bumper, and aftermarket bumper (PW-SP-210) which the bolts are countersunk and will be covered by an aftermarket bumper.