4PK Refillable Ink for HP 88 OfficeJet Pro L7480 L7590 L7700 L7500 L7600 L7750 L7550 L7650 L7780 L7555 L7680 L758 L7681 K5400 K5400tn K550dtwn K5400dn K550 K8600 K5400dtn K550dtn Ready to use: Cartridges are pre-filled & ready to use Easy Refill: A pre-made hole makes it easy to refill the cartridges Innovative Design: Our cartridges are spongeless. This eliminates streaks caused by air bubbles from the sponge. Experience sharp clean prints. Cartridges are also transparent so that ink levels are clearly visible. No more leaks when refilling! Superior Quality Ink: Our high quality UV resistant dye-based ink will yield closest quality to OEM inks.