1/8" SC shape carbide burr, single cut, ball nosed cylinder.
A rotary burr for deburring, weld dressing, shaping and blending in a die grinder or air tool. This one cuts 1/8" diameter with 9/16" of cut on a 1/8" shank, 3" overall.
The single cut has one row of flutes, which produces long chips and cuts fast — it suits steel and harder ferrous metals and leaves a rougher surface.