QR code printed on the packaging, approx. But, say, years will pass, the packaging will be lost, reactivation will be required, and what then, where do you order to take it? In general, a stupid toy that costs 5 times more than a regular "analogue" lock with keys, and in fact, difficult to "install", which, by the way, did not work for me. Expensive (relative to conventional analogues, of course) senseless trash. Very annoyed by the senseless waste of time