Generic 950XL Black and 951 Tri-color (Cyan, Magenta, Yellow) Combo Saver 4 cartridges in one pack for Hp Officejet Pro 8100/8600/251/276
If you are experiencing problems there are two easy methods that help with trouble shooting. You can A) take the cartridges out and try putting them back in or B) unplug the printer and than restart it.
