Kit includes trizact discs of 35, 20, 10, 5 micron each; 3 of each grade. Perfect for high-speed steels, it allows sharpening of a wide array of woodcarving and turning tools and knives. Fine hone and maintain the tips and edges of flat chisels, drill bits, counter sinks, fluted end mills, etc. Fantastic results on jewelry: performs better than emery paper and fills porosity. Also works great on plastics and for glass defect repair. Produced with 3M's new microreplication technology, the micropyramids deliver fast, consistent cutting action through their long life. Recommended use with Ninja cushion item number N-3103. Disc size: 3" diameter.