Bosch QuietCast is a name you can depend on, with minimum tolerance levels and innovative materials that ensure the very highest quality and brake judder, noise, vibration, and harshness free operation. All QuietCast rotors are factory mill precision balanced, which disperses the weight evenly, and allows for smooth, safe stops with no pedal pulsation. Performance is ensured by OEM style vane configurations that provide more efficient heat dissipation, reduced vibration for quieter operation, and extended rotor life. Aluminum/Zinc coating protection prevents rust and corrosion, extending the life of the rotor while providing a clean look for today's open wheels. OEM style ABS tone rings (on required applications) provide trouble free operation of Antilock Brake and Traction Control systems. Every Bosch QuietCast rotor features an engraved discard thickness, that lets you know when the rotor has reached its useful life, and an “on-the-part” Bosch brand name, so you can be confident you are receiving an authentic Bosch product.