Slide onto leather. Takes 10 mm flat leather. Glue into position, but dry-fit first! Lead-free. Nickel-free. Designer pack. Plated metal. Some of the clasps are quite stiff to open the first time. Just pry them open and they will be easier the second time.

12mm x 28mm Hole size is approx. 10x2.5. By the pack of 10.