abrasive bits: (1)size100*6mm,115*6mm,125*6mm. (2)used on electric drill,abrasive machine. Mainly used on repairing auto surface. Durable, rigid, long lasting. Aggressive, open-web disc for cleaning welds, removing rust and paint. May be mounted on a straight shaft tool or bench motor. Abrasive mineral: Extra coarse grade silicon carbide. 100*13MM115*13MM125*13MM150*13MM180*13MM200*13MM.