The 658Y Backing plate is made the same ass the 600Y & 500Y. This 658Y Backing Plate is a perfect backing plate made by leading industry Developing professionals this backing plate is made with composite graphite plastic helping it to still have a strong rigid center base. Though the mold on this 658Y backing plate is slightly different made to with stand and re-enforce more rpms from a rotarty buffer. While yet the outer edge is devised of a polyurethane rubber also known as the Flex Edge. This flex edge outer layer was design to provide a more absorbent cushion While buffing over contours of the Car. Build for the toughest of jobs the 658Y backing plate is for use as high as 3000rpm or rotations per minute.