Hey. I make these. Sadly, the piece in the middle (the lock and key) were a lucky find and I have no more. If anyone would be interested in these, let me know. They would make a great day/play collar. I can make different colors, metals, etc, and middle pendants can be custom made. They default with a small/large ring, or a center pad lock, depending.
Clasps can be made more permanent. Once completed, the links for a chain which is both decorative and very hard to break, making it good for all occasions. Gonna see what the response is here before I advertise more.