Solas sf-cd-15/23 Concord Sea Doo impeller has unique blade design that delivers remarkable thrust take off, improves acceleration and top speed 2+mph. Solas sf-cd-15/23 Seadoo impeller is great for pulling skiers to racing 2+ mph gain.. Solas This upgrade over stock Sea Doo Impeller Fits Sea Doo GSX RFI 99-00, GTX RFI 98-02, Boat Speedster 98-99 2x780cc,