Another lightweight, polymer-encased fitness wristband has hit the market. But this one comes from Nike. The Nike+ FuelBand measures time, calories, steps and “NikeFuel.” It uses an accelerometer to measure movement, has built-in USB and 20 LED flights that flash red or green to show your progress, and can connect wirelessly to the iPhone via Bluetooth. The FuelBand comes with a free iPhone app, and is social network friendly, for those users who want to share their activity updates with Facebook, Foursquare and even Path. For now, the FuelBand app is iOS-only. Stefan Olander, Nike’s vice president of digital sport, says that the company will eventually explore other mobile operating systems for the app.