Quick Nuts from CRS are small, clever nuts to attach to the thread of your CRS cymbal holder.
Sometimes, the protective tube can move up the thread slightly. This can be a minor annoyance for some, which is why securing it with a Quick Nut can be helpful.
If you wish to be able to mount and dismount your cymbals from the cymbal stand without having to remove a nut or similar first, you can use the small Quick Nuts to create a cap on the thread that enables this. This requires that you also use the long silicone rubber tubes to achieve a sufficiently stable and protective solution.