Dr. Pulley Variator Kit for Vespa GTS 250/300SPECIFICATIONS: Includes Slide Pieces Does Not Include Roller Weights Number of Splines: 21 Drive Face Outer Diameter (A): 120.5mm Boss Inner Diameter (C): 17mm Boss Outer Diameter (B): 26.9mm Boss Length: 44mm Ramp Plate Inner Diameter Valley to Valley (D): 17.15mm Ramp Plate Inner Diameter Peak to Peak (E): 16.5mmCOMPATIBILITY: Piaggio – Scarabeo 250Vespa – GT250/GT300The Dr. Pulley HiT Clutch with 50 degree pillow springs is for use on scooters with a modified cylinder requiring the clutch to engage at a higher RPM. Results from using this clutch include decreased slippage and improved transmission efficiency.**