Chipless CISS systems with the Chipless Firmware allows the printer to operate without a chip on the cartridge. Many EPSON Printers today have no chip available for a Refillable cartridge. The plus side of a CISS is the ink tanks are on the outside of the printer which allows you to see the ink levels. With no chip you loose the ink levels on the screen. You could use a cartridge inside the printer but you would need to open the printer and remove the cartridge to check the ink level. Most cartridges are small and if you print a lot you will be wasting a lot of time filling the little cartridge.