The video shows:
A. The assembling process for red spring snap ring.
B. How the glass grip works.
In A: the grip pushes the ring to place it in the circular groove of the blue shaft. The ring is expanded during being pushed. It is compressed when the grip moves futher to set the ring in the circular groove of the grip.
In B: when the operator rotates the wheel, the grip translates circularly.
The ring prevents the grip from being removed by a small force.