Turning Point Propellers - 500 Series Hub Kit System - 504 Volvo - 11500400. Turning Point is the only company to offer MasterGuard Installation kits and prop housings for 6-300+hp engines with a Lifetime Warranty Hub. Boaters save up to 33% when buying a replacement propeller housing. MasterGuard hubs are Re-useable most of the time after a prop strike, and if not, they are Warrantied even if the prop is Destroyed. These hubs offer enhancedlower unit protection. Turning Point's MasterGuard Hubs