Product review (5 stars): Excellent, powerful, USB power NOT REQUIRED!
UPDATE: there is a tab the battery needs to slide under (see picture, tweezers pointing at tab that needed bending upwards) and my battery was on top of it as received. Bend that tab upwards, slide the battery underneath so it comes in contact with the (+) side and you don't need USB power for logging (although that is still optional, which is nice as I don't know how long the battery lasts.  You can even squeeze  2477 BATEERY IN THERE BUT YOU HAVE TO TAPE THE BACK UP CAUSE THE COVER WONT FIT SEE VIDEO.

I LOVE the flexibility of the software, the size, price, accuracy, ability to calibrate: it is all here. I have always dreamed of a device so simple and cheap yet configurable. Buy now!

 Note: you need usb power for these to be "logging". probably in the fine print somewhere, you would think if it requires a battery that would be good enough so an assumption was made. For the price though? Wow. software exports to excel, pdf, even can auto email to you but setting up the server is beyond me...assuming this thing is hooked up to a computer that is always on. may be wrong about that.