Bomtech - Do-All - Revo Permanent Makeup (PMU) Cartridge Needle - 4F (One Box with 15 Needles)Revo needle cartridges are EO sterilized disposable needle cartridges with new patented technology that allow for the adjustment of pigment flow through the needle cartridge. ADJUSTMENT Adjust the amount of pigment emission by turning the adjustment ring. If you close the adjustment hole, a small amount of pigment is dispensed into the skin; If you open the adjustment hole, a big amount of pigment is dispensed into the skin; No other needle cartridge