1/4" SE shape carbide burr, single cut, oval shape.
A rotary burr for deburring, weld dressing, shaping and blending in a die grinder or air tool. This one cuts 1/4" diameter with 3/8" of cut on a 1/4" shank, 6-1/4" 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.