The addition of oil or water during grinding results in a finer finish, cooler grinding and longer tool life The flexibility of the disc during surface grinding is determined by the hardness grade of the holder. Abrasive: Aluminium oxide A Available grit sizes: 100 G (coarse) = yellow brown 180 M (medium) = red brown 240 F (fine) = blue Suitable for general work on metal surfaces e.g. removal of rough grinding traces, removal of oxidation and for light deburring work. For safety reasons, the maximum permitted rotational speed indicated must never be exceeded