Busch recognized as the world leader for premium quality burs, widely used in the jewelry industry. Busch burs are manufactured on high-tech machining centers using proven, state-of-the-art technology. Made of tungsten vanadium steel for strength and durability. Teeth are precision machined and uniformly spaced so cutting is accurate and smooth. These Busch Burs are offered in this listing in 2 separate sets: 1st Set Contains Busch Fig. 1 Round Burs in sizes 5mm, 6mm, 7mm, and 8mm 2nd Set Contains Busch Fig. 1 Round Burs in sizes 5.5mm, 6.5mm, 7.5mm, and 8.5mm Please chose appropriate set or both if necessary. Maximum safe speed varies with bur size and is indicated on the box. Burs measure approximately 1-3/4" long with 3/32" shank. Made in Germany.