We have 2 wifi printers from HP but only one of them is labeled Air Print. Said unit (HP 6500A) has never performed consistently even for the MBP co-located with it in the same room. I use the older 8500 in my office. I can easily print to it from my MBP and now with the app I mentioned above. That 6500 often can be seen by my 4S, iPad, and my MBP but always returns an error when I try to use it.