myzone switch. ****used 6 times**** The world's first interchangeable exercise tracker for the gym, outdoors or in water.Monitor your heart rate on your chest, arm or wrist. Three times the motivation and three times the fun, with a light indicator and built-in memory so you can see your zone without a phone, and up to six months battery life on one charge. all 3 bands, charger, bag and device. I bought it for the gym I was planning on joining. (didn't join) Questions? Leave a comment below!