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. The Max Bias is a new version of the Maximum Results. The Maximum Results was one of the last cores Mo Pinel designed, featuring one of the industry’s highest intermediate differentials. With the addition of the new HK22+ cover, we can move the breakpoint further down the lane, yielding a more dynamic down-lane motion. The Max Bias has Mo’s signature design written all over it. Lots of hook and lots of motion. With the Max Bias core numbers RG 2.494, a total Differential of 0.050, and a strong Intermediate Differential of 0.030 combined with the HK22+, you have the most hook potential from Radical in several years. Color: Blue/Aqua Coverstock: HK22+ Textured Hybrid Core: Maximum Results Asymmetric Cover Type: Hyrbid Reactive Finish: 500, 1500 Siaair Micro Pad RG: 2.494 (15# ball) Differential: 0.050 (15# ball) Int Diff: 0.030(15#ball) Recommended Lane Condition: Heavy Oil Manufacturer's Warranty: Two years from purchase date