nice picture of the tape rule, but your item is not very clear. Camera is maybe focusing and adjusting it's light sensitivity to the bright yellow of the tape rule. Can you try another picture of the item alone, for greater detail? The rule pictures already give us it's proper size.
It looks like a hinge that was used on old cabinets, tins with lids, and I think on some clipboards and binders, that tange works like a spring to keep the them closed.