Burning cutter material: alloy, coated with durable diamond particles at the head; Shank Diameter: 1/8"(3mm); Total Length: Approx. 45mm. Compatible with most rotary tools, the excellent grinding effect of diamond burrs makes your DIY projects much more efficient! 30pcs assorted diamond burrs, offering different shapes of cutting heads to choose from: round/cone/spherical top cone/cylindrical/cone point/needle. Suitable for jewelry making, model building, jade carving, craft modeling, fashion design, home repair and other fields. Ideal rotary burr for engraving ceramics, gemstones, wood, jade, glass; Perfect for fine detail work, cutting, engraving, carving, touch-up and finishing. Features Quantity: 30pcs Material: Alloy Surface: Coated Diamond Particles Shank Diameter: 3mm (1/8 inch) Total Length: Approx. 45mm Ideal for drilling materials up to 1/2" thick.