The 100 Grit TR30 (photo shown is 150 Grit) is a tapered diamond bur with a rounded end. The approximate head length is 8.5mm, the approximate head diameter at the base is 2mm, and the approximate head diameter at the tip is 1.3mm. This bur is great for grinding or carving all types of stone, glass, tile, wood and more... It works especially well for creating small carvings. This shape works especially well for blending areas on a carving or free form. The 100 Grit is intended to be used for bulk removal and rough cutting. As with all Lasco Diamond Burs, the 80 Grit TR30 is a high quality, durable, 100% Natural Diamond bur, and is made in the USA. The TR30 is also available in 100 Grit, 150 Grit, 200 Grit, 400 Grit, and 600 Grit.