Considering a ring dòrbell

Hi Everyone, i strongly thinkking of purchasing a video doorbell in the near future. Just a a couple of questions about initial installation to pacify my mind.Firstly, how is the doorbell powered, i assume its some kind.of rechargeable battery, is it possible to power via a 240v mains adapter, and secondly, it the video footage able to be saved to a mobile device or PC and what file format would it be saved as?I thank you all for your help and comments as although i consider myself to be quite technology savvy, I know adlbsolutly nothing about theseMany ThanksJohn B