Reset the pages reported on drum count to 28K pages using this chip.  You get 4 chips for 4 seperate resets in this one purchase.  You can re-use a drum up to 2-3 times simply by replacing the chip or until imperfection or smudges appear on the prints.  Works for HP Color LaserJet 8500, 8500n, 8500dn, 8550, 8550n, 8550dn,  8550gn, and 8550mfp (drum C4153A).