On an S-Clasp, you attach a soldered ring to each side, and then attach your string of beads to each soldered ring. On one end of the clasp, you maneuver the curved wire so that the ring cannot slip off it. On the other end, you maneuver the curved wire so that there is a bit of an opening for the ring to slip off, but only after some resistance from the wire.You don't want too much of an opening where the ring could slip off without any kind of resistance from the wire.