We carry Garmin Rally Upgrade Pedals for both the Rally XC100 and Rally RS100 power meters. These upgrade pedals allow you to quickly and easily transform your current XC100 or RS100 power meter into a dual-sensing power meter. With a dual-sided system, you can measure power from both legs. This will increase the accuracy of your power data. It will also allow you to monitor you left vs. right leg power distribution.