Polar M400 review: A feature-packed GPS running watch that can also track your steps and sleep - CNET
Amazon.com: BoxWave Cable Compatible with Polar M400 (Cable by BoxWave) - DirectSync Cable, Durable Charge and Sync Cable for Polar M400 : Cell Phones & Accessories
BoxWave Cable Compatible with Polar M400 (Cable by BoxWave) - DirectSync Cable, Durable Charge and Sync Cable for Polar M400 : Cell Phones & Accessories - Amazon.com
Polar M400 review | TechRadar
Polar - Not only a color, but a state of mind! For those of you who fancy a little splash of color to brighten up your day. Polar M400 is now available
Tech Review: Polar M400 GPS Running Watch - That Shelf