HP OfficeJet 720

HP 51629A (HP 29) Black Inkjet Cartridge
51629A Black Inkjet Cartridge compatible with the HP DeskJet 600/ 660/ 670/ 672/ 680c/ 682c/ 690c/ 692c/ 693c/ 694c/ 695c/ 695cci/ 697c/ DeskWriter 600/ 660/ 672/ 680/ 682/ 690c/ 693/ 694/ Fax 910/ 920/ OfficeJet 380/ 50 Also fits NCR/ Digital Check/ Apple/ Pitney Bowes/ and Sony. The use of compatible supplies does not void your printer warranty.

HP 51649A (HP 49) Tri-Color Inkjet Cartridge
51649A Tri-Color Inkjet Cartridge compatible with the HP DeskJet 350/ 600/ 610// 612/ 630c/ 632c/ 640c/ 642c/ 648c/ 650c/ 656 cvr/ 656c/ 660/ 670/ 672c/ 680c/ 682c/ 690c/ 692c/ 693c/ 694c/ 695c/ 697c/ DeskWriter 600/ 660 Also fits some Apollo/ Apple/ and Sony. The use of compatible supplies does not void your printer warranty.