While the Nike+ FuelBand was announced a couple of weeks ago, it has now spent its requisite time under the lens of the FCC, giving away a few more details about what we can expect from the fitness wristband when it launches later this year. Software for the device will be available for both PC and Mac, but you'll also be able to connect via Bluetooth to an iOS app, allowing you to monitor your data, upload it to your NikePlus.com account and alter the FuelBand's settings on the move.

The FCC's documents have also given us a glimpse of the tech packed inside the tiny plastic loop: a flexible circuit board holds the Bluetooth radio, with the antenna etched directly onto the silicon to allow it to be squeezed into the smallest space possible. One of the photos (below) shows how the circuit board fits into the three size options, and there are also details of how the diameter can further be adjusted by adding or removing extra links to the strap. And while there's no listed battery life, the radio is set up to sleep when not in use to preserve the operation of the device. The FuelBand's set to ship on the 22nd of this month, though it seems that consumer demand has outstripped Nike's expectations — the pre-order page already lists the band as sold out.