NEW 12" Osaka Diamond Face Industrial Grinding Wheel 6140402, 325 Grit.  New old stock from a closed auto parts manufacturing facility.

6140402
T10742001
305-75W-3X-80H
SD325-5-MED3

12" Diameter
3.15" Bore
2" Thick
1/4" Abrasive Material Thickness
Brass plate between diamond abrasive and steel body.

This is an extremely high quality industrial wheel with exacting tolerances and superior construction.