The greatest thing since the invention of sliced bread. Use the bead stopper instead of tape or a stopper bead to prevent your beads sliding off the end of the cable before you are ready to attach a clasp or whatever. Fabulous, fabulous, fabulous. Squeeze the rings and open up and clamp on. So effective and simple, you'll wonder why you didn't think of it yourself. Stop thinking about it and just buy some! They are so useful - you get 5!
By the pack of 5.