The Fitbit Flex wireless activity & sleep wristband is designed to track your steps, distance & calories burned during the day, as well as your sleep quality at night. This slim & stylish water-resistant device wakes you up with a silent alarm that won't bother your partner. The wristband is powered by Fitbit's leading-edge MEMS 3-axis accelerometer & automatically synchronises your statistics to your computer or smartphone to provide real-time access to the stats on the Fitbit dashboard throughout the day. It comes with a free online tool & a mobile application & offers a free Fitbit account.