Layout: 75 degrees x 4 1/2" x 40 degrees RG: 2.62" Differential: .019" M/b: n/a Surface: 1000 Grit Sanded Core shape: Symmetric Manufacturer's Intent: The Concept redefines how core and cover combinations tackle challenging lane conditions, delivering a level of control and consistency that reactive balls alone often can’t achieve. Its ARC™ Pearl Coverstock acts as both the engine and the tires, gripping the lane to create continuous, predictable motion through the pins while