We just launched a Bluetooth Smart Stride Sensor!
The Stride Sensor measures running speed, cadence & stride length and sends this data to any Bluetooth Smart ready device real time.
Polar Beat users (iOS) will receive real-time running data during each training session, and the Running Index feature will provide a detailed breakdown of the user’s performance figures, allowing him or her to track his or her progress and even estimate projected finish times for long distance events such as marathons.
It works inside and out, so will give accurate data even on a treadmill or in cities with tall buildings. http://www.polar.com/us-en/products/accessories/Stride_Sensor_Bluetooth_Smarthttp://www.polar.com/beat/