Metronome & tuner application that you can use to improve your performance.
You can change the BPM and bar of the repeating sound.
Also has a tuner with some common guitar tunings, to more quickly change your tuning.
A subscription is required to use the application. A trial period is available as well.
Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/