Back in the early 70's Roto Star, the predecesser of Roto Grip, sold the X-2, a rubber ball with, as I remember it, a three piece weight block. The ball came with the top, side, and finger/thumb weights marked on the box and was supposed to be drilled lined up on a star emblem on the ball. When a crate of these balls came in we all tried to be the first to look at the weights so we could select the exact weight distribution we wanted. They performed better (or at least we thought they did) than the other rubber and plastic balls on the market at the time. -- JohnP