The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From Engineered Stuff:
Stereo Mic Tools will allow you to quickly recall the Microphone Type, Microphone Angle, and Microphone Separation values for several well known stereo microphone configurations and see their Recording Angle and Recording Angle 75% (RA_75%). Use your device camera to measure the Performers Angle and accurately measure and set up your mic angles.