Solas ys-df-14/21 Dynafly impeller will give increased acceleration and top speed 2+mph. Solas ys-df-14/21 yamaha impeller pitched and balanced for performance. Waverunner impellers are great for racing to pulling skiers...​This upgrade over stock Fits Yamaha FZR, FZS 08-13, FX Sho 08-up, FX Cruiser SHO 08-up also great for Stock to Stage 3 kits. Also replaces 6S5-R1321-03-00