The Scosche myTREK Wireless Pulse Monitor is a comfortable new workout tool for managing pulse, training type, calories burned, music and more with your iPhone, iPod Touch or Android Smartphone and RunKeeper’s website. The Scosche myTREK has no bulky chest straps or wires and easily attaches to your forearm for full wireless communication with your device. Integrated dual LED/optical sensors produce real-time pulse monitoring. The Scosche myTREK communicates with a Scosche myTREK application on your wireless device. Track your previous workout stats such as pulse, calories burned, distance/speed, workout duration and overall progress with the integrated calendar feature*. Includes small, medium and large armbands to fit any arm size. Please note that the Scosche myTREK Wireless Pulse Monitor does not communicate directly with the RunKeeper application. Data is synchronized with the RunKeeper website after an activity is completed and saved using Scosche's myTREK application. *Distance/speed/pace/maps on devices with 3G/4G network services only.