App info is currently processing and/or the app is not yet fully available for sale on the US App Store. IMO, it should do more at the regular price point before requiring IAPs, but, for free, it's worth checking out if you want to test/work on your frequency recognition.
It works for me but I'm not an audio engineer so I can't say how useful it will be for you ... But it's under 15MB and free ... So grab it while you can and see what you think.
