Guitar Tuner allows Android users to tune their guitars. This application was downloaded from Android Market more than 250 000 times and now it's actively used by 50 000 people all over the world.
User chooses a string one after another, makes a sound and in the application tries to fix a diamond in a centre by tuning the string.
Application's main displayTuner works for 6- and 7-string guitars and for 4- and 5-string bass guitars as well.
Choosing a guitar display