Set of two cartridge racks for the ZeroG/Quick Change airbrush system. Holds 12 paint cartridges. You can mount them using two or three m4 machine screws, or mount them with magnets that have m4 mounting screws available on amazon. These are part of the Zero Hero system, but this listing is for the brackets only. 3d printed to order in PETG for toughness and chemical resistance.