Myzone-3 Physical Activity Chest Strap Heart Rate Monitor USED Exercise tracker and heart rate monitor with built-in memory and unrivaled versatility. Belt up, collect MEPs and go for your goals. The MZ-3 connects easily to your phone, favourite cardio machines and screens in the gym so you can workout your way. Go phone-free with built-in memory and make every workout count. Join millions of Myzone users and find your squad. Fun, fair fitness.