The Garmin heart rate sensor with Soft Strap keeps a close eye on your heartrate. Wear it on your chest and the velocity of your heartbeats is measured directly. The pulse is transmitted to your Garmin GPS device, so you can keep a close eye on this. This is the renewed model.
To prolong the life span, Garmin recommends to wash the strap every time with lukewarm water after working out. (obviously without mounted sensor). After 7 times of working out you wash the strap and your clothes in a '' delicate-net '' soft washing program.