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. We’re Hammer, and we’re not going to do things like everyone else, thus, the Raw Hammer series. There are four incredible-looking and performing Raw Hammers to initiate this series. The difference with these balls is, we took performance and being unique into account. This series was created to enhance a Hammerhead’s bag and gives newer bowlers performance options with their first Hammer purchase. All Raw Hammers contain the original Raw Hammer core and come in 10 through 16 pounds. The uniqueness is in the cover and finishes. The Black Raw Hammer uses a solid version of the Juiced cover and has a 3000 Siaair finish, providing more hook potential and performance at this price than any ball on the market. In addition to the solid Black Raw Hammer, there is an orange/black hybrid Raw Hammer and two fantastic-looking pearl balls, purple/pink/silver, and blue/silver/white. COLOR: Blue/Silver/White PERFORMANCE: Lower Mid CORE: Raw Hammer WEIGHTS: 16-10 Pounds WARRANTY: Two years from purchase date COVERSTOCK: Juiced Pearl COVER TYPE: Pearl Reactive FINISH: 500, 1000, 2000 Siaair / Crown Factory Polish LANE CONDITION: Light to medium oil REACTION: Skid / Flip