I bought this and later saw reviews that said it wouldn’t work with an Android phone. Tried it any way, and it sync’d fine with my Galaxy S4. First I tried to just hold the plastic part against my chest and it wouldn’t sync, but when I hooked it into the strap and tried again my app (Endomondo) found it fast. To my surprise I could monitor my heart rate and connect my bluetooth headset at the same time.

Basic bluetooth heart rate monitor, tells me my heart rate and when connected to the app mapmyfitness tells you the calories burned, all in all it seems accurate and doesn’t drop signal
No bells and whistles but it gets the job done

I just received this in the mail today. I have a Samsung Galaxy S5, and I had some difficulty pairing it at first. MapMyRun would not pair it at all, but RunKeeper, which I use anyway, connected easily. I then tried to connect the sensor to my iPad using MapMyRun, it connected really fast, and after that, it connected to MapMyRun on my phone as well. I don’t know why it paired easily after the iPad but just thought I’d post this since other reviewers had trouble using it with android devices. It’s now pairing easily to either app. I haven’t gone running yet but it worked really well during a short walk. I can’t wait to go on my next run using this.