This ball fits at the very bottom, just ahead of plastic or urethane. It is my new ultimate control ball, never, ever overreacts; urethane-like ball path and reaction, with strong resin hitting power. Mine is sanded to 2000 grit dull/matte from the stock 1000 grit. I've played 4th arrow at Nationals and 1st board in local leagues, with the same ball
You can fit 1 - 2 more levels of oil handling balls between the Charcoal and the Blue/Green.
Absolute "must have" for every bowler no matter brand you love.
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"None are so blind as those who will not see."