These Sterling Silver Earring Clip Levers are used with the Earring Clip Lug 264/21LU. The lugs are first soldered or joined onto the item and then these clips are fitted onto the lugs. They may work as replacements for clip earrings that are missing the clips but still have lugs attached but they may not if the lugs are different than the 264/21LU.
Also available for purchase with the lugs, see part number 264-21.