Bev Fox, of Sleeping Fox Inc., owns a US Patent on her jewelry clasp, the ‘Chameleon Swivel Lock’. This clasp can be used on chains, beaded pendants, bracelets, as well as hinged designs. The best feature of this clasp is that it locks to prevent jewelry losses. It’s easy to put on and it seamlessly blends into the design. You are welcome to try to duplicate this.