This grinding stone bit set of 5, is for sharpening and grinding metal Universal Fit Grinding Stone Bit Set is used for various kinds of electric grinder, grinding machine to remove burr & surface grinding Universal Fit Grinding Stone Bit Set comes with Cylindrical (large) – (Overall length: 72+/-2mm, grinding head diameter：32+/-1mm, grinding head length：32+/-1mm, shank diameter：6+/-0.1mm), cone – (Overall length：70+/-2mm, grinding head diameter：29+/-1mm, grinding head length：30+/-1mm, shank diameter：6+/-0.1mm), cylindrical (medium) – (Overall length：71+/-2mm, grinding head diameter：19+/-1mm, grinding head length：37+/-1mm, shank diameter：6+/-0.1mm), cylindrical (small) – (Overall length：62+/-2mm, grinding head diameter：19+/-1mm, grinding head length：32+/-1mm, shank diameter：6+/-0.1mm) and ball – (Overall length：55+/-2mm, grinding head diameter：25+/-1mm, grinding head length：25+/-1mm, shank diameter：6+/-0.1mm) Shaft material: Steel