In the base execution, GR TRASCO couplings are available in two different versions:precision P or economy S. The difference between P and S type hubs is that inthe precision execution the circular sections of the hubs are precision machined, while inthe economy execution they are simply deburred. The S version allows lower axialdisplacement as indicated in the technical performance table. Hubs are available in castiron GG25, die cast aluminium alloy or forged aluminium. On special request hubs areavailable in steel or cast iron GGG40.TRASCO couplings are dimensionallymanufactured to hub types A , B and "L" (long hub execution).