Take control of your game on drier lanes and pound the pocket with the new Hammer Spike! A High RG, High differential core system. Coverstock: GTRIII (Hybrid version of the Taboo Jet Black"s coverstock). Finish: 4-stage Process: 800 Abranet, 1000, 2000 Abralon with Powerhouse Factory Finish. Oil: Drier Lane Conditions. 12# RG 2. 60 Diff . 039. 13# RG 2. 53 Diff . 055. 14# RG 2. 59 Diff . 047. 15# RG 2. 56 Diff . 054. 16# RG 2. 57 Diff . 054.