Enormous clamping force with small flaw

The clamps hold in my amateur photo studio laid the background materials and they do very well. The clamping force is convincing and also prevents the slip rubberized interior or "migrate" the ferrule.

A small drawback is the red parts at the tip of the ferrule. These should be adapted to what is clamped. However, they often fold with me to the outside.

Otherwise perfect :-) I would take them back.