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.
Bud/Flame Burs have a gently curved taper that comes to a point. Similar to a cone bur, they are useful for tapering, enlarging holes, or repositioning holes, and for a variety of stone setting tasks.
High Speed Steel (HSS) burs strike a balance between cost and durability. They maintain their hardness (temper) better than vanadium steel and cost less than carbide steel.