925 Solid Sterling Silver 8mm (0.31") Black Onyx Adjustable Screw Clip On Earrings This listing is for 1 new pair of Solid Sterling Silver Screw Back Clip On Stud Earrings. 8mm beads = 0.32" Classic Black Onyx Studs; Hypoallergenic. Adjustable Screw back Clip to fit your earlobes safely and comfortably. Comes gift boxed ready for giving!