The HP DeskJet 3550 uses two ink cartridges: HP 27 (C8727AN) in black and HP 28 (C8728AN) in tri-color. Both are remanufactured, standard-capacity ink. The black is rated for about 220 pages and the tri-color for about 190 pages. The same ink also fits the DeskJet 3320, DeskJet 3322, and DeskJet 3420. Same-day shipping on most orders.
