Interally Threaded Circular Barbells

Internally threaded jewellry is the name of jewellery where the rod is hollow and the ball has a threaded pin that is threaded into the rod. On externally threaded jewelry, the thread sits on the rod and is screwed into the hollow ball.

The most common threading is externally threaded jewelry, at least so far, but many studios have started to switch to internally threaded jewelry. The range of externally threaded jewelry is much larger and also cheaper.