Genuine OEM HP PSC 1315 v Ink and Supplies
With the PSC 1315v, the HP 27/28 and HP 56/57 combos both cover black and tri-color ink. The twin packs serve a different purpose: they contain two HP 27 black, two HP 56 black or two HP 57 tri-color cartridges, not a mixed black-and-color pair.
Toner Buzz carries genuine HP ink from all four families, plus HP 58 photo ink. Singles keep the order focused on one ink type; choose the 27/28 or 56/57 combo when you need black and color in the same purchase.