There is little room for privacy when it comes to what this thin bracelet knows about its user. A great way to get in shape this summer, Fitbit Flex wrist band tracks steps taken, distance covered and calories burned while using small LED lights in the band to show the wearer's progression toward his or her personal goals. Keep the band on overnight and it will track sleep cycles and the number of times slumber was disturbed. In the morning the band vibrates, alerting the user that it is time to start the day without ever disturbing his or her partner. The Fitbit Flex automatically syncs data with other devices allowing users to track trends and progress throughout the day.