Monitor your heart rate while you exercise with this GPS that tracks and displays your heart rate zone and sends the data to a compatible Garmin device.
I got this to pair with my Ant+ phone (Xperia Ray). It works exactly how it should & is comfortable to wear - I've even slept with it on a couple times to see my sleeping heart rate. Bestbuy.com had the best price.
What's great about it: Much more comfortable than I thought it would be.