How does a temporary fastener work?
The temporary fasteners are used to hold heavy panels in place before fastening them completely.
That way the panel is already in place and on the correct position.
By turning the hex nut and so tightening the spring, the jaws ((2) on below drawing) open up and so fixing the temporary fastener.
When it’s fully opened, you have a length of for example 25mm and it can be pulled back to 0.