Carbide Cutter Three Blade Counter Sink by Yu Xuanjie 1.00" / 25.4mm with .3185" / 10mm Hole

Will Fit a 3/8" Short Drill +/- a few Thousandths or 10mm +/- 

Can be used independently to face without a drill bit.

Premal's Tips:

Use shim stock wrapped around to secure drill bits smaller than 10mm.