3M Cartridge Roll 341D, Straight, 3/8" Diameter x 1" Length, P120 Grit (Pack of 100) Small size is ideal for sanding and finishing hard-to-reach spaces X-weight cloth backing supports heavy sanding yet frays to expose fresh abrasive Resin bond withstands high heat and pressure Aluminum oxide abrasive in a closed-coat layer provides fast cut and long life Rolls attach to a compatible cartridge roll mandrel (sold separately)