The broken image link also ate the text, which was apparently along the lines of:
"I've had this for 50yrs and I have no idea what it is. Anyone care to take a stab at it? It's ½" drive, the outboard 'points' are adustable for width, the center point is stable. I don't believe it's for a marine fuel cap or a urinal canister for inline 'cakes'. Too flimsy and it also pivots/flops from side-to-side."