Check the listing for details. Roto Grip Clone 15lb Bowling Ball NIB. Color: Multicolor, Condition: New. Listed at 149.95 USD. Brand New in Box 15lb Roto Grip Clone Bowling Ball. Here's what Roto Grip has to say about Clone:CLONE - "a thing that duplicates, imitates, or closely resembles another in appearance, function, performance or style." And well, since the last version of this core part was unwillingly abducted, we felt it was our responsibility to the entire bowling galaxy to "clone" it and mix in a few upgrades & performance enhancing tweaks that bowlers of all skill levels on planet earth will benefit from. And just as before, the reasons that led to the creation of the original E.T. Core that featured out of this world core technology better known as “equalizer cavities” to emulate the use of a balance hole, the CLONED E.T. Core also does that, but MORE.