316L Internally Threaded CZ Horseshoe Ring - 16G, 5/16"
What is Internally Threaded Post?
Internally threaded post has a threaded hole inside the post, and then an external thread protruding from the stud. A smooth post passes through the piercing, and then the stud is inserted and screwed into place.
The Association of Professional Piercers (APP) sets the standards to be followed by professional body piercers, and they make their position very clear in regards to threaded jewelry: Internally threaded jewelry is part of the APP standard for initial piercing jewelry: the part of the jewelry that passes through your skin is smooth, and the threads are on the removable end(s), such as balls, gems, or spikes.
Internally threaded jewelry avoids any possibility of scraping your tissue with sharp threads, which is especially important with fresh piercings."