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. Track Theorem Solid Bowling Ball ? Perfect for Medium to Oily Lanes The Track Theorem Solid Bowling Ball is engineered for control, power, and precision on medium to heavy oil patterns. Building on the success of its hybrid and pearl predecessors, this solid edition introduces the new Super Response Reactive coverstock?offering aggressive traction through the front and mid-lane while maintaining a sweeping, smooth backend motion. At the heart of the Theorem Solid is the MC2 Asymmetrical Core, delivering a strong and consistent motion with plenty of hook potential. Finished at 2000 grit, this ball grips early without burning up energy, making it a reliable benchmark for tougher lane conditions. Whether you're navigating transitions or need a dependable first ball out of your bag, the Theorem Solid delivers tournament-ready performance every time. Visually striking with its Black, Blue, and Purple color blend, this high-performance ball not only performs like a pro?it looks the part too. Key Features: Super Response Reactive Coverstock: Enhanced traction and control in medium to heavy oil MC2 Asymmetrical Core: Designed for a strong, sweeping motion with predictable backend 2000 Grit Surface: Helps the ball read the mid-lane without sacrificing backend power Reliable Benchmark Motion: Ideal for players needing a dependable shape across changing conditions Standout Design: A bold Black, Blue, and Purple colorway that performs and impresses Specifications: Brand: Track Line: High Performance Bowling Balls Color: Black / Blue / Purple Coverstock: Reactive Cover Name: Super Response Reactive Core Shape: Asymmetrical Core Core Name: MC2 Asym Core Surface Finish: 2000 Grit Flare Potential: 4 ? 5 Inches Recommended Lane Conditions: Medium ? Heavy Oil Available Weights: 12LB, 13LB, 14LB, 15LB, 16LB Scent: None