The Shim features Big Bowling’s benchmark symmetrical Powder Keg Core combined with their P5 Reactive cover in a Pearl version. The performance of the Powder Keg Core is aptly named: like a real powder keg, the fuse is slow and steady, but with explosive results at the pins! The “P” in the P5 Reactive coverstock stands for “Predictable” with a hook rating of 5 on a scale of 1 to 10; This very low RG ball allows the ball to read early while the P5 Reactive cover gets it down the lane. This creates smooth motion steady from start to finish; However don’t let the motion fool you as the unique dual-pyramidal design with central elongation creates late tip with readable flip giving this ball amazing motion through the pins. Sometimes you need a late motion to play the Shim in order to give you explosive results where it counts!