Vertix Academy Round Liner (20pcs)1 box contains 20 cartridges Vertix Academy Needle Cartridges deliver trusted quality and precision you expect, with a simplified design and straightforward performance that make it easy to focus on the work. Whether youre stocking kits, training programs, or simplifying your day to day setup, these artist favorite cartridges keep it clean, consistent, and accessible. Product Highlights: Wide Compatibility: Works with all standard cartridge machines