The UltraFoam Weighted Bowling Ball is manufactured from the same foam rubber material that we developed for our extensive line of UltraFoam products, including bats, balls, polo sticks and Round-N-Flat products. UltraFoam is a virtually indestructible material that s super soft, super safe (to players, bystanders, walls and furniture) and affordable. One of its unique properties is the ability to absorb and dissipate the shock of impact, while still providing significant kinesthetic feedback. UltraFoam is also colorful and washable. Weighs 2-1/4 lbs. (1.1kg) and guarantees exciting pin action. Its 6-3/4″ (17.1cm) diameter and an exclusive multi-grip handhold pattern provide a one-size-fits all bowling experience.