For ink jet printers. Compatible with Epson WorkForce Pro WF-4730, WF-4730DTWF, WF-4720, WF-4740, WF-4734, EC-4030, EC-4020, EC-4040, WF-3820, WF-4820, WF-4830, and WF-4840. This maintenance box is used and will fill up during printhead cleanings, power cleans, and more.