This is an earring BACK, or clutch, that is part of the earring design. It takes an 11 mm or ss 47 Rivoli - or - you can use a 12 mm as well - it just overlaps a little. This goes on the back of the post, behind your ear, and curves forward, so that you get a stone hanging down and forward, to complement the main earring. It's definitely a show stopper! Rivolis and post not included.
By the pair.
