This bowling ball ships PRE-DRILLED. There are 5 sizes and the sizes that we drill are based on the weight of the ball. X-Small: 6lbs- Ages 8 and under, Small: 8lbs and 9lbs- Ages 8-11 and womens ring size from 8-11, Medium: 10lbs, 11lbs, and 12lbs, Ages 11-15 and Adult Ring size 10 or lower, Large: 13lbs and 14lbs, Mens ring size 10-12 or people with larger hands, X-Large: 15lbs and 16lbs, Mens ring size over 13 or people with extremely large hands. If you would like a different size drilled for the weight you selected, you must contact us via email as soon as your order is placed with your order number. Pre-Drilled bowling balls cannot be returned or exchanged. Every Track ball is created for a specific purpose; each new ball fills a gap and advances the arsenal. The Sensor Solid is a unique blend of power and control that will conquer a variety of medium to heavy oil conditions. The power and ability to handle oil come from the MR-6 Solid cover, finished with 2000-grit Siaair. The Regulator is a lower flaring core that provides control and consistency, as recently found in the Sensor Pearl. The Sensor Solid is a great option for any level of bowler and is the ultimate choice for dominating the lanes. PERFORMANCE: Mid COLOR: Orange / Scarlet / Burgundy CORE: Regulator COVERSTOCK: MR-6 Solid COVER TYPE: Solid Reactive FINISH: 500, 2000 Siaair Micro Pad LANE CONDITION: MEDIUM OIL WARRANTY: 2 yrs from purchase date RG (16 lbs)2.503 (15 lbs)2.49 (14 lbs)2.506 (13 lbs)2.574 (12 lbs)2.597 DIFF (16 lbs)0.029 (15 lbs)0.034 (14 lbs)0.034 (13 lbs)0.040 (12 lbs)0.040