DIAMOND 4mm MED GRIT BULLET
Diamond electroplated burs and drills are for use on materials such as glass, ceramics, stone, and metal. They are even good for clean up work. These stainless steel burs have diamond particles electroplated on them in a medium/fine grit (120-140grit). The shanks are 3/32" (2.38mm).
These diamond burs are a premium/professional grade that are manufactured to last many times longer than cheaper diamond points.
Remember to always use water or a diamond lubricant when using diamond instruments of any kind.