These ball chains are made of strong metal alloy and are much higher quality than other plastic or nickel-plated chains found elsewhere. #3 (2.4mm) size connectors can used to close the chain to make a necklace or keychain (Connectors sold separately). Perfect for dog tag or pendant necklaces, keychains, blinds or retaining chains, the applications are limitless! These CleverDelights-brand chains are top-quality and exclusively licensed by CleverDelights for sale on Amazon. Don't get burned by cheap, low-quality imitators.