Amazon.com: BoxWave Cable Compatible with Polar M400 (Cable by BoxWave) - DirectSync Cable, Durable Charge and Sync Cable for Polar M400 : Cell Phones & Accessories
Polar M400 review: A feature-packed GPS running watch that can also track your steps and sleep - CNET
Polar M400 GPS Smart Sports Watch and Fitness Tracker (Black)
Polar - #TeamPolar, we've got a bunch of updates for you: - M400 and V800 firmware - Flow web service - Flow app iOS And the icing on the cake: Flow app
Polar M400 review | TechRadar
Android phone compatibility issues with Polar products | Polar Global
A quick update on Polar's planned software updates | DC Rainmaker
Polar M400 sync does not start in FlowSync. Now what? | Polar Global