There isn’t a person on this planet that will argue against the fact that Hammer made the best urethane bowling balls back in the day. There is no doubt in our minds bowlers looking for the ball reaction that dominated the 80’s and early 90’s will find it in the new Purple Urethane Pearl! This is ball is 100% real urethane and offers that true urethane reaction. 15# and 16# balls feature a thick shell. 14# balls use an outer core system.