Clamshell bead tip ends - also called calottes - are a nice finishing touch - and are often seen on traditional knotted pearl strands, but are useful anywhere you need to attach a small, sturdy loop.
To use, pass the thread through the hole in the middle back of the "clam" from the outside of the clam, and make a knot inside big enough to not pull back through the hole. If this is a challenge, tie a knot around a small bead that will fit inside the clam. Then, fold the "clam" shut using your pliers. Then you can use the loop to attach to a clasp - or whatever you want, just add the clasp etc and curl the loop closed with your pliers.
By the pack of 24.