I picked one up to see how it worked. I've got the iOS app which the unit pairs with, but it isn't showing the 10kg calibrate button. I've not mounted it to a bike, but am hesitant to do so until I can at least know that the app is capable of doing the calibration.
@PhilDAS let me know if you find a solution to the app problem! Now I just need some cranks to put them on..