 The measurement is in millimeters and doesn't vary by much, but it has to be precise. We depend on AutoZone to ensure we're ordering the correct parts. AutoZonePro.com makes it easy, laying out the differences clearly, including pictures and application guides. We were able to order the quality Duralast pads and rotors for the Passat, which helped us get our customer back on the road the same day. Learn about Duralast OE quality parts at DuralastParts.com, exclusively available at AutoZone. That's DuralastParts.com.