The Speed Ring is a "Chinese flying top" and the high speed model of Duncan's very short-lived Jo-Jo line, which was produced in the late 60's or early 70's. It was discontinued and taken off the shelves due to poor sales.
The units that were removed from market were destroyed, so very few of the Jo-Jo toys that were already purchased before the line's discontinuation remain. As a result, it is almost completely forgotten, as there is very little information on it.
The idea behind the Speed Ring and any other "flying top" in the Jo-Jo line is that it works like a miniature diabolo, except that the string is not attached to any handsticks and is thicker than the standard yo-yo string. They also use a deep groove clutch for easy balancing, along with collapsible body halves which can be folded up for carrying or pulled outward for play.
The Duncan Jo-Jo line, along with other similar toy products such as the Milton Bradley Yo-Go, can be considered the unsung predecessors of all offstring yo-yos.