This app is only useful for owners of foc.us products.
If you don't own a foc.us product get one at www.foc.us
foc.us make electrical brain stimulators featuring tDCS, tACS and tRCS.
They also make an awesome EEG Dev Kits which can read your brainwaves.
But to repeat, if you don't own any of these devices then this app is not for you.
With Family Sharing set up, up to six family members can use this app.