What is external threading? What is internal threading?
Externally threaded barbells have threads on the OUTSIDE of the barbell. So the ball has the threading on the inside. Most small gauge and most medium gauge jewelry is externally threaded. Internally threaded barbells have the threads on the INSIDE of the barbell. So the ball has a threaded stud that goes inside the barbell. When you start moving into the bigger gauge barbells, internal threading provides greater comfort and cleanliness. Take a look at threading styles here.
