This ball ships professionally PRE-DRILLED for your convenience. We?ve simplified the process so you can hit the lanes faster. Based on the ball weight you choose, we?ll drill it to a standard hand size that fits most bowlers in that weight range: X-Small (6lbs): Ages 8 under Small (8?9lbs): Ages 8?11, women?s ring size 8?11 Medium (10?12lbs): Ages 11?15, adult ring size 10 or under Large (13?14lbs): Men?s ring size 10?12 or larger hands X-Large (15?16lbs): Men?s ring size 13+ or extra-large hands Want a different drilling size than standard? Email us immediately after checkout with your order number and your preferred size. Roto Grip Rockstar Amped Bowling Ball ? Power, Precision, and Pure Energy Ready to dominate league nights? The Roto Grip Rockstar Amped is built for bowlers who crave backend power and consistent control. Designed for competitive players and league warriors alike, this high-performance ball thrives on medium to heavy oil patterns, delivering a clean read through the fronts and an explosive backend finish that turns heads and crushes pins. At its heart lies the Rocker + A.I. Core, an advanced symmetrical design that optimizes energy transfer for faster revs and exceptional continuation. The enhanced A.I. structure fine-tunes core dynamics for more flare and a strong, angular backend motion ? ideal for modern lane conditions. The low RG (2.48) and high differential (.050) combination gives you that trademark Roto Grip motion ? smooth through the midlane and fierce at the pocket. Wrapped around this powerhouse core is the NanoStar Pearl Reactive Coverstock, built using a medium load of nanoparticles for consistent lane traction. With Storm?s Power Edge Finish, the Rockstar Amped clears the front with ease before unleashing a decisive move at the breakpoint ? perfect for bowlers seeking length and a sharp backend angle. Whether you?re chasing titles or stacking wins, the Rockstar Amped blends power, predictability, and polish like no other. Step up, fire your shot, and let the energy amplify. Specs at a Glance: Coverstock: Roto Grip NanoStar Pearl Reactive Core: Rocker + A.I. Core (Symmetrical) RG (15lb): 2.48 Differential (15lb): 0.050 Finish: Storm Power Edge Polish Flare Potential: 4?5 Inches Best For: Medium to Heavy Oil Patterns Color: Purple / Red Performance Level: HP3 Series Scent: None Available Weights: 12?16 lbs