Flap discs combine grinding and finishing in a single disc — the overlapping abrasive flap construction removes material while simultaneously leaving a smoother surface than a rigid grinding wheel. In stone work they're used for edge smoothing, surface preparation, and blending transitions between grinding and polishing stages. 

Pro Tool Haus carries flap cup wheels for stone grinding, standard flap discs for metal and general fabrication, and diamond-coated flap discs for hard stone and ceramic applications. All for use on standard angle grinders with 5/8"-11 threads. 

For Proxxon MICROMOT flap discs (50mm for LHW/E and LHW/A), see Proxxon Flap Discs. For the full grinding and stock removal range see Grinding Coring Stock Removal.