A tattoo needle is a long, thin bar with sharp pins soldered
onto the end. They are more commonly used with coil machines
than with rotary machines, and usually need to be
attached to the machine with a grommet. Tattoo cartridges are a newer
invention, and have rapidly become the industry standard. In these, the needles are contained within a
plastic shell which allows you to draw more ink onto the needle. Cheyenne-type universal cartridges are the
industry standard, and they attach with just a twist.