Introducing the Tacx Speed & Cadence sensor. This Training accessory is a great way to keep an eye on your cadence when training & also gives an accurate reading of your speed. This is for use with a Tacx trainer that does not already automatically read speed & cadence via the trainer itself. This can help you train more specifically & help you figure out what the most efficient cadence for you to spin at. Overall this is a handy training buddy as it will help you become more efficient in your cycling.