Your Sigma Rox 10 communicates via ANT+ radio standard. In order for you to get the most out of your Rox with all its functions on a second bike or to buy spare parts, Sigma offers the speed sensor, cadence sensor and heart rate chest strap as separate components. The Sigma ANT+ cadence sensor for mounting on the left chainstay wirelessly transmits your current cadence to the Rox 10 on the handlebars via ANT+ radio signal. This keeps you in control of your basic training and makes it more efficient. - Purpose: universal use - area of application: Sigma Rox 10 bicycle computer - function: cadence transmitter.