Polar M400 review: A feature-packed GPS running watch that can also track your steps and sleep - CNET
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
M400 displays "cancelled" at the end of charging? : r/Polarfitness
Amazon.com: BoxWave Cable Compatible with Polar M400 (Cable by BoxWave) - DirectSync Cable, Durable Charge and Sync Cable for Polar M400 : Cell Phones & Accessories
USB Charging Cable M400 Charger Compatible with Polar M400, M450, A360, A370, V700 Sports Watch USB Charger Cord - Newegg.com