Merit Abrasives Sand-O-Flex Resin Bond Refills Abrasive strips backed by eight cushioning brushes for good conformability. Refills are available both scored (for finer, less aggressive work) and unscored. Load quickly and easily by turning the index knob as needed, allowing you to change grit size in minutes. Fit most electric drill and bench grinders. RPM will accommodate most electric drills Pack of 1