Apple Nike+ iPod Sensor

The Nike+ iPod Sensor from Apple is designed to be used with a pair of Nike+ shoes to track your workouts using an iPod touch (2nd generation or later) or iPhone (3GS or later). For use with an iPod nano, you'll also need the wireless receiver included in the Nike+ iPod Sport Kit. The sensor fits into the built-in pocket under the shoe's insole and pairs with your iPod or iPhone via 2.4GHz wireless technology. It makes an ideal replacement or spare to have on hand.