I bought all four colors and Monoprice said the chip was revised for HP recognition, they were not, the printer gave me an error when I installed them. I believe the cartridges are still useable, but I have only just started using them.
This works very well in the Office Jet 8600 printer. It does give a warning that it is not a "HP Cartridge", but it works fine. I have never had a problem with any of the cartridges I have purchased from Monoprice.
I received two of these cartridges and neither of them worked. Monoprice, like always is awesome and is going to refund me. Not sure why they didn't work. I ordered all the color too and only magenta worked.