Train more effectively with Garmin's Premium Heart Rate Monitor. When worn around your chest during an activity, it wirelessly transmits your heart rate to your compatible device for instant feedback on how hard youre working. The strap is made from a soft fabric for more comfort. The size is adjustable to your body so it stays secure during your activity. Once its paired with your compatible device the first time, it will automatically recognize it each time. & it's optimized for use in crowded areas like the gym & road races, so it wont 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 h&-wash the strap as often as needed. Features Strap Length: Adjustable from 533.4 mm to 749.3 mm Weight: 45g Battery: User-replaceable size CR2032 (3 volts) Battery Life: Approx. 4.5 years (based on average use of 1 hour per day) Operating Temperature: -5C50C Range: 3 m