Pyramid Chosen One Bowling Ball SG 19.5 Asymmetric Core, 2.52 RG, 0.043 Differential, 0.015 MB Differential (High Flare Potential) XF Gravitational Hybrid Coverstock with 2000-Grit Abralon/Factory Polish Finish Gives Controlled Angularity motion on Medium-Heavy Lanes Versatile drilling options for different bowling styles USBC Approved Equipment