The Polar M400 is a waterproof GPS running watch and daily fitness and activity tracker, letting you train smarter and more optimally. Paired with a compatible Android or iOS smartphone, this gives smart notifications of calls, emails, calendar events and messages, as well as push notifications from social media apps. This also gives you access to the Polar Flow app, which lets you personalise the watch to your specific training needs. Without your phone, it still has integrated GPS allowing you to focus on your training, with manual and auto lap sensors for running.With a rechargeable battery lasting up to 8 hours of training time using both bluetooth and GPS, this allows you to push your limits and is easily recharged using USB cable.This product is shipped with the Polar H7 chest heart rate monitor strap, but is also compatible with the newer Polar H10 chest heart rate sensor.