Labret studs are used in pierced lips.One end is flat for a comortable fit inside the mouth, it´s made to ease the stress on your gum.This jewellery is very easy to wear and it´s very easy to change the appearenc of it by just replacing the screw on ball.
Replacment balls will be found in the "Spare Beads/Balls etc." catagory.
There are two options when it comes to threaded body jewelry: internal threading and external threading. With internally-threaded jewelry, the shaft is the "female" part of the jewelry, and the "male" (post) part of the jewelry is attached to the decorative end(s).The opposite is true with externally-threaded jewelry. External threading means the "male" post is attached to the jewelry shaft (or, more typically, carved into the shaft), and the decorative ends contain the "female" part--i.e. the hole that the post screws into.