Hands-on: Microsoft's fitness band
The new Microsoft Band is a "device like none other", according to Matt Barlow, the company's general manager for new devices.
It tracks heartbeat and footsteps, but also combines email and messages from a smartphone.
But is it too ugly to be popular? The BBC's Rory Cellan-Jones put that suggestion to Mr Barlow ahead of the device's international launch.
Follow Rory Cellan-Jones on Twitter @BBCRoryCJ