These flywheels utilize RPS's patent pending "segmented" heat shield system. Traditional heat shields warp because of the uneven heat produced by a slipping clutch. Just like a car going around in a circle, the outside tires go faster than the inside tires, the clutch disc slides faster around the outside of the flywheel than it does around the inside. The faster moving outside gets hotter than the inside. Because metal expands more the hotter it gets, the outside of the heat shield expands more than the inside. Traditional heat shields are made of one piece metal rings, so when the outside expands more than the inside, the only thing the shield can do is warp. The RPS Segmented heat shields are not connected so they can expand and contract without warping. A warped heat shield causes the clutch to slip, which causes more heat and more warpage. RPS Billet Flywheels are dynamically balanced after CNC machining. Other flywheel manufactures assume that since they CNC their flywheels it comes off the machine fully balanced. This would be true assuming the density of the aluminum is constant throughout the part. Unfortunately even the best billet material is not evenly dense throughout. RPS Billet Flywheels weighs 12.5lbs. and are fully rebuildable.