These cup chain ends can be attaches to the last link of the chain by sliding them from the back and closing prongs on top. You will need prong closing tool or pliers to close the prongs.  Cup Chain End w/Ring 3mm (12ss) GOLD...

The Charm-Round Ball Drop with Loop 3mm Gold Plated is a small and elegant jewelry component with a ball drop and a loop for easy attachment to necklaces, bracelets, or other jewelry. Its understated design adds sophistication and glamour to any jewelry...