R&D G-FORCE SPONSON'S are designed and tested to deliver superior cornering, unmatched speed, and improved straight line stability. R&D Pro Series Sponson Kits main feature includes an ultra strong cast aluminum CNC machined backing plate, which is far superior over plastic backing plates with furniture inserts for threads! R&D Sponson Kits offer more adjustability than the competition, which will guarantee to out perform any other 1 up, 2 up, or 3 up! The R&D Pro Series Sponson Kits offer a smoother more predictable ride with much better low and high speed turning capabilities! Track tested and race proven!