Bottom Cartridge Priming Tool is designed for use on the black and tri-color cartridges. This tool helps clear clogged nozzles, draws the inks down to the printhead remove air bubbles and bottom refill. Cartridge clips are also used when refilling and / or for storage of cartridges. For use with Canon black & color cartridges: Canon PG-40 50 830 CL-41 51 52 831 Package includes: - 1 Primer tool - 4 Syringes with needles