This is one of many similar "analytical" weight scales or "fat scales" - described as capable of measuring body fat, water, muscle and bone weight/percentage. I bought the cheapest one (~$10, so basically same price as "regular" weight scale) but there are many similar ones, sometimes slightly more expensive. I think they can be recognized with metal stripes on the front and three buttons: up/down/set. They are sold under many brands, with some cosmetic differences, powered by 2 AAA cells or single CR2032.
Buttons are actually mechanical and located on the side.
I was thinking that this weight scale uses some kind of frequency/impedance analysis, but it seems to me now that it actually measures only weight. Body components percentage is just guess, based on entered height/gender/age (there are 12 memory cells for personal data). Metal strips on the top are not even connected to anything, just attached to glass with double sided tape. Also, percentage measurements does not change regardless of if I'm stepping on it with bare foot or in (isolating) shoes.
As metal strips have no function, I've removed them. This leaves glass plate flat and thus easier to clean.
In conclusion - if you are looking for real analytical weight scale, don't buy this one.
