●✅3 x 21 Inch,12 PCS, all 40 Grit ●✅The belt interface is firm and will not break easily By the Diagonal lap splice technology ●✅Made with Premium Aluminum Oxide grain ●✅Antistatic, washable plus an additive in the resin to resist loading ●✅They are mainly used for wood / aluminum / non-ferrous metal / glass / plastic / stone ect