While Supplies Last, and Extremely Limited. Product - Round Liner Needle Cartridges Needle Size - Standard #12 Needle Gauge/Diameter Brand - Turbo Sterilized - EO Gas Sterile Quantity - 12pcs/box Compatibility - These cartridges are industry standard and will fit all machines and grips. These cartridges use a spring system to retract the needle, and are not as stiff as the Cheyenne Cartridges. Please note that these cartridges DO NOT have a Membrane and there is a small chance of ink blow back. Tattoo Pen users should be cautious that ink blow back could damage your machine. We will not be responsible for any damage caused from use of our needles.