The Polar A370 is an updated version to the Polar A360. The A370 is an intelligent, powerful wrist-based fitness tracker with continuous heart rate readings without wearing a chest strap. You can even use the A370 as a heart rate sensor by pairing it to your favorite fitness app. The A370 utilizes your smartphone's GPS capabilities to provide you with critical data while you train. The sleep plus feature not only records your sleeping patterns but also detects when your sleep has been interrupted in order to provide you with more useful feedback.- Strapless Heart Rate: Have the A370 intelligently track your heart rate through the twists and turns of everyday life.- Assisted GPS: Use your phone's GPS to track speed, distance, and route.- Improved Sleep Analysis: Get the valued insight you need to get a good nights rest.- Broadcast Heart Rate: The A370 can be used as an HR sensor. Pair it to your favorite fitness app.- 3rd Party Compatibility: Exercise and activity data is automatically sent and is available to be used in services where you allow it. Connect your Flow account for example to Apple Health Kit, Google Fit, and MyFitnessPal.- Mobile Connectivity: Seamless communication via Bluetooth Smart to Polar Flow app on mobile devices.- Smart Notifications: Get an alert whenever you receive a call or a text.Featuring Polar Smart CoachingPolar's unique Smart Coaching feature offers the best possible guidance on how to develop your training as well as helpful feedback on your progress.- Sleep Plus: The A370 tracks not only the timing, amount, and quality of your sleep but also automatically detects when your sleep is interrupted.- Activity Benefit: When it comes to an active lifestyle, even the small things make a difference. Learn how your everyday choices benefit your health and well-being.- Running Program: Whether training to set a personal best in a 5k or running your first marathon, set a race target and let our online program guide you towards your goal.- Training Benefit: Need some motivating feedback after your work out? Polar's Training Benefit immediately explains what type of physiological benefit you gained from your training.Continuous Heart RateTracking your activity is more than just counting steps. Polar A370's wrist-based heart rate monitor intelligently tracks your heart rate 24/7, giving you a more accurate look at your daily activity and calories burned. Easily see how your heart rate responds to the peaks and valleys of your day.- Tracking your activity is more than just counting steps. Polar A370's wrist-based heart rate monitor intelligently tracks your heart rate 24/7, giving you a more accurate look at your daily activity and calories burned. Easily see how your heart rate responds to the peaks and valleys of your day.