- Expired Cartridges - PRACTICE USE ONLY. NOT FOR REAL SKIN. Product - Nuto Round Liner Cartridge Needles Needle Size - Standard #12 Needle Gauge/Diameter Brand - Nuto® Sterilized - Yes Box - 20pcs Cartridges What are Nuto® Magnetic cartridge needles? Most cartridges use a membrane, spring, or rubber band to retract needles back to initial position . When your machine pushes the needle out there is back force being put on your machine causing stress and wear on your machine. This is why some cartridges require stronger motors at a higher voltages to work. With Nuto Cartridges, there is no added stress to your machine. The top of the cartridge connects to the machine via a heavy duty magnet, essentially creating a standard loop bar. The needle then follows the motor in and out of the skin at the same rate as a standard on bar needle while keeping the benefits of the safety cartridge. With this zero-resistance design your machine will last longer and work easier at lower voltages. If you haven't used NUTO before, please try our Sample Pack. Sample pack includes: 4pcs of each: 3 Round Liner, 5 Round Liner, 5 Round Shader, 7 Magum, and 9 Magnum. NOTICE - These cartridges are not compatible with Cheyenne machines. These cartridge needles work with NUTO-Compatible machines or require you to use our magnet loop bars. Loop bars come in 3 lengths: 82mm, 85mm, & 91mm.