Train hard, run free. The running dynamics pod easily clips onto your waistband to measure the running dynamics you need to Beat yesterday. It gives you the option to run Without a Heart rate monitor chest strap but still be able to view and analyze your cadence, Stride length, ground contact time and balance, Vertical oscillation and Vertical ratio. These biomechanical measurements can help you understand your running form so you can perform better on race day. With a replaceable battery that lasts more than a year, this pod is easy to use. Once paired with your Compatible Watch, just clip it to the back and center of your waistband and start your run. It's so tiny, you may forget it's there.