Fitbit F004 Ultra Tracker clip-on fitness tracker Blue & Black Working Excellent. Pre-owned, used condition, has 2 chips on both sides of tracker shown in pictures. Accurately tracks your calories burned, steps taken, distance traveled and sleep quality Simply carry it in your pocket or clip it to your clothing, and the Fitbit automatically keeps track of your fitness and sleep. Anytime you walk by the included wireless base station, data from your Fitbit is silently uploaded Contains a 3D motion sensor like the one found in the Nintendo Wii, which tracks your motion in three dimensions and converts this into useful information about your daily activities