The Fitbit Charge 4 is a fitness and activity tracker that helps you monitor your daily activities, track your workouts, and measure your heart rate. It features built-in GPS, allowing you to track your outdoor activities without needing to carry your phone. With its sleep tracking feature, you can monitor your sleep patterns and get insights into your sleep quality. The Fitbit Charge 4 is a popular choice among fitness enthusiasts, making it one of the top movers and shakers in the sports and outdoors category on Amazon.