Plate colour indicates disc density for easy identification in the workroom
It is used in conjunction with a disc pad hub (sold separately), which attaches to the power tool, and is held into place along with the appropriate disc using a retainer nut (sold separately)
This assembly allows the disc pad face plate to be easily changed without removing the disc pad hub, allowing the operator to use a single tool for multiple applications from heavy grinding to finishing a workpiece
Ribbed face plates provide additional force when needed for optimal fracturing of the abrasive mineral