3/8" SL shape carbide burr, double cut, ball nosed cone.
A rotary burr for deburring, weld dressing, shaping and blending in a die grinder or air tool. This one cuts 3/8" diameter with 1-1/16" of cut on a 1/4" shank, 2-1/8" overall.
The double cut crosses two rows of flutes, which breaks the chip up small, keeps the tool from grabbing and leaves a smoother finish with less vibration.