to butirfli
one end of the key served to make the skate longer or shorter when you flipped it over and adjusted the nut.If I remember correctly most of the girls on my street used to use an old shoelace as a necklace to wear the key.There was also a felt material on the underside of the clamps,I think it was either red or green.I haven’t thought about those skates in many years until I read your posting.