This device is a next generation GPS built-in running watch and fitness tracker, which includes built-in heart rate monitor. With this watch you can track steps, distances, burned calories and sleep. In case of getting notifications, device will vibrate. Device is waterproof and it can take 30 meters depth. It’s compatible with Android and iPhone devices, but you can sync up your data with PC or Mac, too.
Polar M400 is designed for runners who want a comfortable and durable running watch with sporty design and advanced GPS and training features. Track and record running as well as your other exercise, and monitor your performance accurately. Just like Polar M200, this device is waterproof, until you reach 30m. It’s perfect for swimming. Battery life can be up to 8h training time (when both GPS and HR in use). It can last up to 24 days in time mode with daily activity monitoring. This item has a rechargeable battery with standard micro-USB cable.
Here’s some interesting videos about both of them: