A:Answer Hi Refiller, The refill bottles are designed to fit individual printers. Make sure your printer is designed for Epson 502 refill bottles. There is a label in the ink fill area on your printer that shows the correct ink bottle number. If you have the correct bottles, try turning them on the valve until they fit the keyed nozzles. Once they are coupled correctly, press the bottle straight down and the ink will run until the tank is full then stop. For instructions and videos, visit the Epson support page for your EcoTank. Regards, Mark - The Epson Team.