Guitar Tuner : Hz

Guitar Tuner is one of the fastest, easiest and most accurate tuner apps with a simple interface. 
—Accurate electronic tuner : professional accuracy down to less than 1Hz precision
—Easy to use interface : no complicated menu, just pick up your guitar and tune it
—Auto detection of which string is played : don't click on any button, play any string and let the tuner figure it out
The app offers many different tuning modes and tools, as well as a list of standard and alternative for guitar and ukulele tunings.
Supported :
Guitar
Guitar Electric
Guitar Bass
Ukulele