Race sponsons. This boat is just plane scary at high speed with the OEM sponsons, it tracks on the smallest boat wake and is very unpredictable. The worx sponsons are easy to fit, they just bolt straight into the factory inserts in the hull and you don’t need to get into the inside of the hull at all. The difference is remarkable, it changes the boat to a really safe predictable ride and you can turn as hard as you like without ant risk of getting thrown off or spinning out of control. WORX RACE SPONSONS High performance sponsons are manufactured to specific designs to suit each boat from H.D.P.E. (High Density Poly Ethylene) a very tough solar resistant material. All sponsons are supplied with full detailed set of instructions and all necessary stainless steel hardware to install the set of WORX Sponsons. Fits all Ultra 130, all Ultra 150 and all Ultra DI.