This is a smartchip replacement for the HP 5500 and HP 5550 color toner cartridges. The OEM HP laserjet 5500 and laserjet 5550 toner cartridges have "smartchips" which are used to monitor how much toner is left in the cartridge. They are also used as tools to prevent refilling your cartridge and saving hundreds of dollars, so that you are forced instead to buy brand new OEM HP 5500 and HP 5550 toner cartridges at ridiculously high prices (in excess of $300). If you refill your HP 5500 and HP 5550 cartridges, the printer will not recognize the refilled cartridges and not allow you to print with them. BUT THERE IS A SOLUTION! Replace the smartchips with our HP 5500 and HP 5550 smart chip replacements, they are easy to install and are guaranteed to restore your cartridges to "LIKE NEW" specifications, allowing you to successfully refill and print with your cartridges. Choose from HP 5500 / HP 5550 black, cyan, yellow or magenta smart chips.