The Garmin Premium Heart Rate Monitor lets you train more effectively. When worn around your chest during an activity, it wirelessly transmits your heart rate to your compatible device for instant feedback on how hard you're working. The strap is made of a soft fabric for more comfort. The size is adjustable to your body so it stays secure during your activity.Once it's paired with your compatible device the first time, it will automatically recognize it each time. And it's optimized for use in crowded areas like the gym and road races, so it won't pick up any signals but your own. Taking care of it is a snap. The plastic heart-rate module is removable from the strap so you can wash the strap as often as needed.