A backup plate is required for safe operation of flexible grinding wheels.
For 4-1/2" flexible grinding wheels with a 7/8" center hole — use MMM #51046 Flexible Grinding Wheel Backing Pad, which is 3-3/8" in diameter, with a 7/8" center hole.
For 7" flexible grinding wheels with a 7/8" center hole — use MMM #51045 (available by special order) Flexible Grinding Wheel Backing Pad, which is 4-5/8" in diameter, with a 7/8" center hole.
This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm.
www.P65Warnings.ca.gov