... used in atomatic grinding machine for polish granite slab,strong sharpness,average grit, good abrasion strength and low cost.ItemGritRemarkL140mm ... L170mm Fickert AbrasiveNormal typeROUGH 816Magnesian bond ,long life ,good at safety and efficiency.24#36#46#60#MEDIUM ... is better than LUX01# . High brightness, low cost, good at safety and efficiency.Bakelite back.(fickert abrasive,abrasive,granite ...