Key Signature APP for iPhone

[Phatty]

I ran into a number of key signature identifier apps, but they don't go into detail as far as if they include a bass clef. I was wondering if anyone had any experience with any of these apps. I'd like to practice my key signature id whenever I can, thanks.

[colcifer]

Learning the circle would be better because than you'd know how to figure it out and what the sig means, dig?

On a related note, I have a cool idea for a theory app if anyone on here is an app maker (I know the irealbook guy was a tber at one point).