The Roto Grip Gem features the new Defiant LRG core and the very aggressive MicroTrax Solid Reactive coverstock. This strong reactive cover was seen previously in various formulations on balls like the Idol, Halo, and RST X-1. The Defiant LRG asymmetrical core is a modified version of the core that was found in the Defiant series of bowling balls. With Roto Grip’s lowest RG (2.47″) in an asymmetrical design, this is a core that is designed to rev up, and it is wrapped in coverstock that grips the lane with its rough 2000 Abralon box finish. All of these elements come together to create a ball that is made to hook.

Stroker loved the reaction he had with the Gem on our heavy oil test pattern. It easily allowed him to play more swing on the fresh than he usually can, thanks to the strong continuation at the back end. The dull finish and aggressive cover made sure the ball always hooked as he moved farther left in transition. There have been very few bowling balls that have given Stroker this kind of look on BTM’s slickest test pattern. Stroker had the best reaction of the three testers on our fresh medium pattern. The dull box finish ...