Runtastic Heart Rate Combo Monitor: Bluetooth Smart + 5.3kHz. The Runtastic Heart Rate Combo Monitor uses the latest Bluetooth Smart wireless technology to transfer your heart rate data to your Runtastic apps, without an additional adaptor for your smartphone. In addition to tracking your speed, pace, altitude, distance, and duration, the data provided by this training equipment will make your workout statistics even more useful and reliable. The Heart Rate Monitor also has a 5.3 kHz signal, which allows it to work with most cardio equipment in the gym (e.g. treadmill). Use our all-in-one combo heart rate monitor for all your fitness activities!