The Fitbit Charge 2 Heart Rate Fitness Activity Tracker in Black is a compact and versatile device that offers a variety of features to help you track your fitness goals. With a display resolution of 161 x 160 and a variety of measurement options including heart rate, time, and calories, this activity tracker is designed to provide accurate and detailed information about your workouts. The device can be worn on the wrist or hand and is compatible with Windows, iOS, and Android operating systems. Additionally, the Fitbit Charge 2 includes sensors such as an accelerometer, gyroscope, GPS, and compass to enhance its functionality. Whether you're into gym training, weightlifting, yoga, or running, this activity tracker is a reliable tool for tracking your progress.