The CS100 has all of the bike-specific functionality of the CS100b, including a wireless speed sensor, an option to upgrade to a wireless cadence sensor, plus the ability to mount the system on either a handlebar or stem. What sets the CS100 apart, though, is that it comes standard as a full-on heart rate monitor. It comes with a Polar T31 coded chest strap, plus Polar's OwnCal, and OwnCode capabilities in order to give you an array of HR-specific data. You can easily review current, max, and average heart rate, calorie consumption, as well as customize training zones.