The Bali twisted wire S clasp is my favorite. It's an easy size to handle, especially when fastening and unfastening behind your neck, and it is more secure than a toggle clasp. I like that it goes with everything from a simple necklace to one that is more ornate.
This is my all time favorite necklace clasp. It can be quickly modified for a right-handed or left-handed person. It won't tarnish - at least I haven't seen one tarnish yet; and I've been using them 3 or 4 years. It's beautiful! What more can you ask for?
This clasp turned out to be just right for a heavy stone bracelet . Lovely design and finish. Strong and affords a good grip for hooking onto the provided 7mm closed jump rings. Clasp measures 20.5x8mm.