Check the listing for details. Fitbit Flex Wireless Activity Tracker - Blue (FB401BU) Includes Original Box. Color: Blue, Condition: For parts or not working. Listed at 10.00 USD. Fitbit Flex fitness and sleep wristband tracker. Will light up and appears to charge when inserted into the charger and wiggled a bit. Software found it when attempting to synch but I was unable to successfully complete the process. Selling as is for parts or not working. Includes pebble, one band (size large), charger cord, PC dongle and original box The Fitbit Flex Wireless Activity Tracker in Blue (FB401BU) is a fitness technology device designed to track various activities such as gym workouts, yoga sessions, and running routines. With features like wireless connectivity, Bluetooth capabilities, and a wristband design, this activity tracker allows users to review their data, monitor calorie intake, set alarms, and track sleep patterns.