This is similar to the gyroscopes we had in the early 1950s, and it works exactly the same way. You thread the string through the hole in the axle, and turn the gyro until the string is wound up on the exle, then give it a mighty pull to set it spinning. Then you can do tricks with it!
Educationally very good - but a little less fun than I recall because it does not spin for as long or as smoothly as I remember. The vibration is enough to make it fall off its little plastic stand every time we tried it, but it will still do the usual tricks of balancing on a string, albeit not for very long, since it soon slows down. We've tried tuning the adjustable bearings, adding a drop of lubricant, but it still slows faster than one would hope.
The price *looks* a lot more than the 3/6 (threee shillings and sixpence) that I recall them costing way back when, but that translates to about £5 in todays value, so it's fair.
On the positive side, the fairly rapid slowdown means that it will keep a patient and inquisitive youngster engaged longer in rewinding the string and spinning it up again, but it would be nice if it kept going longer.
Whilst spinning, its massive flywheel demonstrates precession well (that weird feeling you get when you move it one way and it responds by moving in another - conservation of angular momentum) and will intrigue the embryo engineers amongst us. Recommended.
Still fascinates me!