We have 4 Salvage Eye Bolts Large Antique items.  They are all the same and measure about 4 1/8" - 4 1/4" in l from the top of the round eye to the bottom of the threaded screw.  The opening on top is about 2" across the center outside measurement, inside is about 1" with the same opening being about 7/8" in d.  The threaded portion is about 5/8" across.  These would be a nice item to repurpose.

4 Eye Bolts Salvage Large Antique