Samsung S21 Ultra The phone has one defect that is not apparent upon inspection, but I will mention it for transparency. After using the device for long periods, for example, 3 hours, without stressing the device, it restarts by itself, and you can use it normally again. I don't know what the problem is, nor did I take it to a phone repair shop. Reason for selling: I bought a new phone and no longer need it. The device is for auction.