Tattoo Rubber Grommets and Rubber Nipples:
Rubber Grommets and nipples are ment to secure the needle bar onto the armature bar, which is on your machine.
View diagram above of a tattoo machine armature bar, and the differences with rubber nipples and grommets.
Most Tattoo Artists prefer rubber nipples than grommets, simple because they are easier to use. A small simple thing like this can change the way at tattoo artist tattoos. ^_^
