These 5 x 5 Grand National style hubs are machined from aircraft quality 7075-T6 aluminum. They are CNC machined to exact tolerances. Hubs come complete with bearing races and 5/8" fine thread studs or optional 5/8" coarse thread studs. The hubs are designed to be used with a bolt on rotor plate that is available to fit the most common rotor bolt patterns or they may also be used with a rotor mounting hat. "WARNING: This product contains a chemical known to the State of California to cause cancer and birth defects or other reproductive harm."