SPEC flywheels are CNC manufactured at an unheard-of .001 tolerance, in an industry where the standard is .010. This precision manufacturing process ensures perfect balance and a perfectly flat bedding surface for the clutch disc, both of which also contribute to the ultimate in safety for competitive environments. All SPEC flywheels carry SFI certification. The aluminum SPEC units are rebuildable and feature a replaceable steel friction plate that is made from a friction-enhancing steel metal specially formulated for optimum clutch bedding and holding power. The aluminum material provides a light and medium weight option for all types of racing.