It comes with two pieces...
and the strap
It pokes out a little, but who cares. No one is looking.
It's easy to set up and easy to use. It literally took me 5 minutes to program it.
I've used the monitor at Fusion and while running. When I've run on the treadmill, the monitor automatically connected with the treadmill and showed my heart rate on the screen. That was a nice little perk!
I picked up mine at Sports Authority, but you can order them online or check your local athletic store. If you've been on the fence about getting a heart rate monitor, I would highly recommend the Polar FT4. If you don't like pink, they have other colors too.
I only wear this when I am working out, but I'm sure you could keep it on all day if you wanted to check your calorie burn, but remember, you have to wear the strap.
**I was not paid to review this heart rate monitor nor did I receive any compensation for this review. I bought this with my own money and my review of this heart rate monitor are based solely on my own opinion.