We carry several other brands of flap discs, but we prefer these from Walter Surface Technologies. We like how the Enduro-Flex flap discs feature trimmable backings made with ECO-TRIM wood fiber backing material. When the flaps wear down to the outer diameter of the backing, trim away 1/4” of the backing at a time (up to three times total). This Exposes fresh abrasive grain, extending disc life and giving you a fresh new cutting edge. See the video here for a demonstration.