This Polar H7 92052229 sensor measures heart rate, then syncs data with your compatible device and mobile training app via Bluetooth Smart technology, so you can easily monitor your workouts. A chest strap offers a comfortable fit.
I find this to be a very accurate heart rate monitor. It's comfortable to wear and the Polar app is a nice compliment for it. The only reason I gave it 4 instead of 5 stars is that it tends to disconnect more often than I'd like and I feel like it burns through batteries quickly with everyday use. But I think Polar makes the best HR monitors so I deal with it.