Make motivation your best accessory with the Alta HR from Fitbit, a fitness tracker wristband that includes heart rate monitoring, all-day activity tracking, sleep monitoring and a reminder for you to move more regularly with a goal of achieving upto 250 steps an hour.Relatively small and discreet it doesn\'t look out of place on the high street and the option of additional wristbands ensure it can always match your outfit, (additional wristbands sold separately). This ensures you wear it more to get a better evaluation of your daily life and encourage you to become more active on a more regular basis. It also connects to your Smartphone to ensure you don\'t miss a thing, with call, text & calendar alerts throughout the day you\'ll always be in the know. You can choose from a variety of clock faces and statistic layouts so you can find the best display for you and the silent alarm can be set to wake you up at just the right time, to ensure you start your day peacefully.Sizing tip: Small: 14-17cm Large: 17-20.6cm