Unlike other reillable cartridge solutions for this printer, the Lyson Bulk Feed System features chipped ink delivery units which can be re-set without removing them from the printer. this ensures that air is never introduced into the ink system and that there is no spillage. the internal ink bladders are sealed off from the outer air chambers, essential fo maintain the ink's integrity as the system is pressurized during normal operation. Compatible with the Epson Stylus Pro 7800 and 9800