This is nice original adjustable generator pulley for an International Harvester Farmall tractor.  It is part number 6746-D and measures about 4 1/8 inches in diameter with an 11/16 inch keyed bore.  These pulleys are nice because they allow you to line up so the fan belt runs straight.  This one seems to be ready for use and should fit several of the letter series tractors as well as several of the early number series tractors.  The pictures tell the story.  I can be reached at 262 573 1931 if you'd like to talk about it.  Good Luck.