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. Charming. Enchanting. Mesmerizing. Call it what you will, but we prefer to call this wonderous and mystical jewel the Magic GEM. After months and months of mixing spell after spell in the R&D Lab, we managed to conjure up one the most prolific hybrid high performance balls we have ever offered thanks to the powers of both the MicroTrax Solid and MicroTrax Pearl components brewed together to form the MicroTrax Hybrid Coverstock. So, if you are looking to put a hex on your adversaries, might we interest you with this powerful magical bowling stone. Trust us when we say, this isn’t just a bunch of hocus pocus. Originally introduced in the GEM, the Defiant LRG Core has brought style, pizzaz and honor scores to bowlers of every skill set around the globe. Thanks largely in part to the density composition of this core, it sets the standard as the fastest revving, strongest continuing, lowest RG asymmetrical core across our lines. So, if strong and continuous is what you are in the market for, then look no further than this part right here. No matter your style or your number of revs on the ball, this core will get into a roll and keep rolling every single time. Color: Citrine/Rhononite/Jet Core: Deiant LRG Core Cover: MicroTrax Hybrid Reactive Box Finish: 2000 Grit Abralon Built For: Medium/Heavy to Heavy Oil RG: 16lbs(2.47) 15lbs(2.47) 14lbs(2.50) 13lbs(2.57) 12lbs(2.59) Diff: 16lbs(.051) 15lbs(.053) 14lbs(.052) 13lbs(.032) 12lbs(.029) PSA: 16lbs(.016) 15lbs(.016) 14lbs(.015) 13lbs(.010) 12lbs(.008)