This part of ISO 6344 sets forth definitions and grain size distribution test for electro-fused aluminium oxide and silicon carbide grits for coated abrasives, i.e.: — macrogrits P12 to P220 — microgrits P240 to P2500 Tests for grain size distribution analysis are defined in ISO 6344-2 for macrogrits and in ISO 6344-3 for microgrits. This part of ISO 6344 applies both to those grits used in the manufacture of coated abrasive products and to those grits recovered from products for test purposes.