This sounds like the biggest loser slim coach. I don't think it is the same thing as a body bug because I believe that takes body temperature readings to give accurate information about calorie burn. This is an accelerometer with some sort of oxygen monitor (no idea how that works) but it goes a bit beyond just tracking how much you move your arm from my understanding although I would assume that it would be a little flawed because it is on your arm.
http://news.cnet.com/8301-17938_105-...ugh-the-paces/
This is the article I read and I think it is a pretty good review of the product with comparisons to similar products.
I actually think the Jawbone Up looks like a more complete product for less money. My issue is that both of these product require you have an iPhone or iTouch I have neither and it is unlikely I will own one for a very long time due to my current finances. If I already had an Apple device of some kind I think I would definitely buy the UP.