This listing contains (4) F6T84AN / 972X high yield black ink cartridges; each cartridge includes a working ink indicator chip that allows you to monitor your ink levels. This set is compatible with HP PageWide Pro 452dn, 477dn, 477dw, 552dw, 577dw and 577z printers. Please note, retail packaging may vary and these cartridges will only work with printers purchased within the United States and Canada. The use of compatible printing supplies does not void your printers warranty. HP does not manufacture LD compatible ink cartridges. We are the exclusive reseller of LD Products brand of high quality printing supplies.