Sky News' eagle-eyed Ed Conway has spotted the chancellor George Osborne is wearing something different to today's Treasury Select Committee:
The tracker is designed to track user variables including weight, sleep, exercise and mood. Osborne said he had been wearing the wristband since he was given it as a birthday present in May, and had spotted education secretary Michael Gove wearing a similar device.
Last night saw Osborne named Beer Drinker of the Year by the All-Party Parliamentary Beer Group at its 20th anniversary dinner for scrapping the beer duty escalator and taking 1p off beer duty. Perhaps he's regretting the drinking and worrying about his waistline?
Retailing at around £100, the Jawbone wristband also lets users attach pictures of their food when tracking their diets (this could explain that Byron burger photo).