Format: retail pkgage: platform: n/astop struggling with chest straps or wearing bulky fitness watches by wearing the lifespan my beat heart rate ring.This monitor provides an easy, unobtrusive way to check your heart rate without interrupting your workout.It features built-in infrared sensors that monitor your heart rate, without chest straps or wires, and measures your heart rate anywhere between 30 to 250 beats per minute.The display shows your heart rate, and can also display time, ambient temperature, and a stopwatch.The watch also includes a training mode that shows your average heart rate, calories burned, min/max heart rate, and training time.The watch has a one size fits all design and includes a silicone insert for greater comfort.