The Polar A300 Fitness and Activity Tracker is the ideal daily companion for both the inspired and those seeking inspiration. Tracking your steps, distance, and calories burned it will let you know your fitness achievement on a daily basis, and gently vibrate to let you know when you need to move. At night, the A300 will track your sleep patterns to balance your rest and recovery with your workouts, and gently wake you at the ideal time in your sleep cycle. Use the Polar Flow App to set goals, track your progress, and compare with your friends.

• Tells you exactly how your fitness is progressing by measuring your aerobic fitness at rest and evaluating your maximal oxygen uptake.
• Shows exactly how many calories you've burned.
• Vibrates when you've been sitting still for too long.
• Automatically tracks your sleep time and quality. See and learn from your sleeping patterns in Polar Flow web service and app.
• Charges conveniently with a simple plug and play USB. 
• Weight 48 g
• Thickness 12.7mm/0.5"
• Water resistant (30 m)
• Display texts in 15 languages
• Updatable software
• Memory capacity up to 60 days (with daily activity tracking and 1 hour of daily training)
• Rechargeable battery
• Battery life up to 4 weeks