Withings little Smart Activity Tracker is, in fact, tiny but a smidge larger than the Fitbit One. It's an odd little shaped device in that it's kind of like Apple's iPod Shuffle if you've ever seen one of those before.
Most of the functions are cycled through using the button at the top but you can cycle through previous days recorded steps and the like by swiping from left to right or vice versa along the lower third of the display. As mentioned before, the SAT does not have an altimeter but a Withings spokesman told me that the technology being used to track stairs climbed is being patented.
Measuring your heart rate seems pretty simple - you simply cycle to the heart rate feature and stick your finger on the LED that's pulsing on the backside of the device.
Withings is still mum on pricing but they expect to ship the tracker by the end of Q1.