FDA approved medical device, same in Europe. Comes with manual. Heres a clip about what it looks like working - https://www.youtube.com/watch?v=4q9wkJWPb5k You detect on your palm where are tingly spots, and those points relate to parts of the body. i found it to be extremely accurate. you change the setting and it sends a pulse through to that area of the body. Only comes iwth 2 ear devices, I found one of them fit me, you just put a bit of hand cream on it for good conduction.