This set of 12 Busch® Wheel burs covers sizes from 0.70 to 2.70mm in diameter. The wheel cutting edge/length increases correspondingly from 0.23mm to 0.68mm. These burs are made of tungsten vanadium steel for strength and durability. Teeth are precision machined and uniformly spaced so cutting is accurate and smooth. Maximum safe speed varies with bur size and is indicated on the box. Use a good lubricant, such as Gesswein Lube-Stik, to facilitate cutting and prolong tool life. Burs measure approximately 1-3/4" long with 3/32" shank. Made in Germany.