Im looking for the one that wraps around your chest with the wrist watch.
Check out Polar, reliable, reasonably priced, big fan.
I use a Polar strap that bluetoooth connects to the Polar Beat app on my phone.
Unless you really just want the watch, you don’t need to buy it.
I use Garmin HRM TRI because it gives me running dynamics so I can see right vs left balance. Also, I have a Garmin watch. It fucking sucks on my third one, they warranty it once though. After the battery dies and you replace it it loses reliability.
Polar makes good ones I would do that if you're looking for something to pair with your phone
Scanwatch by withings is coming out soon
WHOOP! I'm digging mine. It's a 24/7 wrist wearer though. I think it has attachments for around the chest if you want? I got an upper arm sleeve for jiujitsu.