If you own a smartphone, either Android or iOS, Peterson makes a tuning app avialable. The app is basically a software equivalent of their strobe tuner hardware. It is good in that it not onlu is very accurate, but also allows you to see when you are getting close by the strobe display slowing down (the further you are away from being in tune, the faster the display scrolls by, the closer you get, the slower it gets). You also get a cents display (and no, you will not get it to stay at zero cents, just try to get it within 5 cents). It also responds very quickly to any change in tuning, so it will allow you to see the changes as they happen, allowing you to stop when you are tuned properly without delay.
App is called iStrobosoft.