One piece chromoly construction and 6 hole bolt pattern along with a weight of aproximatly 13 lbs. Fot J&G clutches 12-volt 200mm (130 teeth) O-ring style. O-ring part number 311-105-295A sold separately. Material: Chromoly Diameter: 200mm Lightened: Yes200mm Flanged Flywheel Forgedfor Bugpack Crank