iBatto Famous Vintage Analog Metronome

Here you are one among the most accurate metronomes on the store. And yes, it's free.

_extremely high precision engine (beats generated at buffer audio level @44.1Khz)
_30 to 300 bpm (with tap tempo)
_different time signatures
_different beat divisions
_single beat settings (mute, normal beat, accent)
_different sound types
_in app volume control
_really nice graphics with a flipper-style display which worths the money (again, it's free)
_easy to use wheel control to change settings

_iPhone 5 compatible

What else?

Best ticks.
ALTO