Do not buy this. I had one, it never worked, it doesn't pickup your heart rate which means it rarely activates/turns on. 3 months of trying to get it to work and contacting support and they finally sent a replacement. Which doesn't work either. Tested in the gym on other people and with the gym instructors and they won't work for anyone. Even worse is when you contact support half way through the conversation they just stop replying and completely ignore you.