Why would an eleven year old girl have one of these on a string around her neck all summer long? I think you have to be a certain age to answer this question, though I am not sure what that age might be.
My grandparents’ house in Buffalo, New York had blocks and blocks of flat sidewalks. I lived in an area without them, so I was thrilled by the joys opened to me when we went East. I particularly fell in love with roller skating up and down the walks for hours.
In those days, roller skates went on over your shoes and were adjustable to fit various shoe sizes. That was certainly practical when there were so many children in families making it prohibitive to buy skates for each one. The object above is a skate key, allowing you to adjust the sliding sections back and forth by first loosening and then tightening the nuts. The other end was needed to tighten other parts on the skate, especially over the toe.
The skates were bone jarring, since the wheels were metal. They constantly loosened and had to be retightened. I continually fell over, skinning my knees. But in those days, every one I knew had skinned knees. There were a sure sign that you were a kid and it was summer!