Roto Grip’s most iconic line has another new piece coming to it. The Roto Grip Duo features the brand new Mentor Core that yields an RG of 2.49 and differential of 0.046 and is wrapped around the ultra popular microtrax pearl cover. I drilled mine 5.5 x 5 x 5 which is also the same layout as my Exotic Gem. After throwing my Duo for awhile, I was quite impressed on the strength and shape this ball gave me. It was like a little clean benchmark type motion or a better comparison would be a baby Exotic Gem. I can see a lot of people using this as a multi purpose ball. They could either use it on the fresh as a benchmark ball or something as the lanes start to transition. Also Storm is donating 5% of all sales of the Duo to the Big Brother, Big Sister Foundation!