Bluetooth is a low-cost wireless radio transmission specification for creating personal networks of up to eight devices at a distance of 10 to 100 feet.

CNN: Toshiba brings Bluetooth to market

The nano does not yet support Bluetooth 4.0 (or any version of the specification), but the standard has been seen as a key component in helping reduce power consumption for such a product, There are also lower power display technologies -- such as Sharp's Memory in Pixel LCD on the forthcoming Meta Watch -- from which Apple has abstained.

ENGADGET: Switched On: Next for the nano

However, the iPhone 4S's support of Bluetooth 4.0 -- which includes the low-power specification that began as WiBree -- may tip Apple's hand a bit as to its ultimate intentions for the nano.

ENGADGET: Switched On: Next for the nano