3/32" dia. shanks are the jeweler's preferred standard for burs and small rotary tools. They fit the adjustable chucks found on most flexshaft handpieces as well as 3/32" handpiece collets.
Carbide Steel burs maintain their sharpness longer than any other steel. They are more brittle than carbon steel and hss and are more likely to break or chip if mishandled.
Setting Burs are similar in shape to hart burs, but with straight sides. They are used primarily for cutting seats in prongs, bezels and tube settings, often roughing out seats that are then refined with a hart bur.