The Fitbit FB401BK Flex Wireless Activity and Sleep Tracker Wristband in Black is a stylish and sleek device designed to track your daily activities and sleep patterns. With its flexible wristband, this activity tracker is comfortable to wear during all-day use. It is equipped with features tailored for running and jogging, making it a great tool for fitness enthusiasts. Compatible with iOS operating systems, this Fitbit model is a reliable and user-friendly option for those looking to monitor and improve their health and fitness.