Round synthetic white opal ball that sits on top of a 1/4" (6mm) screw style bottom. Great threadless piece that is interchangeable! The ball top can be removed and changed out for a different top so you don't have to buy a whole new piece. Top size is about 2mm. Choose your gauge between 20G and 18G. It is made out of ASTM F-136 titanium and it is a durable material for anyone with metal sensitivities. Sold individually (1 pc).