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 Deadly Rattler is a pearl version of the original Rattler but now features the new HK-22 (Hyperkinetic-22). This cover is setting a new standard by which all coverstocks are being measured. With the addition of the Hk-22 cover, the Deadly Rattler offers a cleaner projection through the front part of the lane and a sharper continuous down-lane motion than the original Rattler. The Deadly Rattler uses the same core as the original Rattler with an RG of 2.48 and a differential of .035. Combining the Rattler and the Deadly Rattler, you get a venomous onetwo punch. LEVEL: Reliable COLOR: Red / Silver CORE: Rattler Symmetric COVERSTOCK: HK22 - HyperKinetic COVER TYPE: Pearl Reactive FINISH: 500, 1000, 1500 Siaair / Factory: Compound WARRANTY: Two years from purchase date RG (16 lbs)2.493 (15 lbs)2.480 (14 lbs)2.496 (13 lbs)2.574 (12 lbs)2.597 DIFF (16 lbs)0.030 (15 lbs)0.035 (14 lbs)0.035 (13 lbs)0.040 (12 lbs)0.040