Cute free app, but despite compliance with the rules (15 min do not drink or smoke before measurement) no reasonable curve recorded. Unclear on the ups and downs. Two beer two per thousand, half a crate of beer 1.5 per thousand. I can display in percent convert, namely myself, but for the price I expect already, I do not have that. And to calibrate the thing to San Francisco to be history. Excellent! So back to the seller.
