The Avalanche Blue/Purple Pearl uses a retro Urethane coverstock. Designed for extra length and a smooth predictable ball motion the Avalanche Urethane is designed for lighter amounts of oil and a more "down the boards" line to the pocket. All Avalanche balls use the acclaimed Teal Rhino Pro light bulb core. The Teal Rhino Pro light bulb core has been at the heart of some of the most successful balls of all time. With its High Gloss Polish surface the Avalanche Urethane will matchup well on dry to mediumdry lane conditions. Shiny surface finishes sometimes cause the ball to go too long before breaking. If your Avalanche Urethane goes too long, dull the surface with progressively rougher abrasives to increase hooking action. The Avalanche Urethane is at its maximum length surface preparation. If your Avalanche Urethane hooks too early, you will need to use a less aggressive ball, such as Brunswick’s T Zone Polyester to create more length. The Avalanche Urethane can be drilled using the standard drilling techniques developed for symmetric bowling balls. At Brunswick, the unique core shape of each individual ball is used for weights from 12 to 16 pounds. This approach to lightweight ball engineering provides bowlers with consistent ball reaction characteristics across this weight range.