Bowling Balls in the Value Performance Category are made of a Urethane material. Most of the bowling balls in this category have a reactive resin additive in the Urethane. These bowling balls are designed for the following: Upgrade from plastic/entry level, affordable, Symmetric Cores, Medium to Medium-Heavy Hook Potential, All Ball Speeds, Light to Medium-Heavy Oil Conditions. Most of these balls have coverstocks and cores from past High Performance Bowling Balls. All balls have a 1 year manufacturer warranty.