Kit includes ceramic discs of 80, 120, 220 grit each; 3 of each grade. Excellent multi-purpose abrasive. Its aggressive bite and non-loading properties are ideal for sanding wood as well as for use on various non-ferrous and tool steels. Jewelers also prefer this material for its performance on precious metals, including grinding sprues off of raw castings. Great results can be achieved when regrinding tool edges that have been damaged or rounded over: chisels, woodturning tools, counter-sinks, drill bits, etc. It's long life and uniform cutting action are among its best attributes. Disc size: 3" diameter.