Monitor your performance as you ride with this easy-to-install, wireless speed and cadence sensor bundleThe cadence sensor fastens to any size crank arm and tracks pedaling strokes per minute, so you can train for your optimal performancedThe speed sensor attaches to the hub of either wheel and self-calibrates with your Garmin Edge to give you accurate speed and distance at all times, even when indoors on the turbo trainer, or in areas where GPS signal is interuptedCompatible with the Edge 1000, 810, 800, 510, 500Now also comptabible with 920XT and FR620 series watch unitsBundle includes speed sensor, speed sensor sleeve, cadence sensor, cadence sensor straps, manual