Polar M400: Running and activity tracking in one (pictures) - CNET

Polar M400: Running and activity tracking in one (pictures) - CNET

Polar M430 first take review: It's an Olympic coach for your wrist - CNET

Polar M400: Running and activity tracking in one (pictures) - CNET

Polar M400 review: A feature-packed GPS running watch that can also track your steps and sleep - CNET

Garmin Vivoactive review: Garmin's first fitness smartwatch misses the mark - CNET

Polar M400: An activity tracker with the heart of a GPS running watch - Video - CNET

Polar M400: An activity tracker with the heart of a GPS running watch - Video - CNET

Polar M400 Review Tested by GearLab

Review: Polar M400 Fitness Tracker Watch

Garmin Vivoactive review: Garmin's first fitness smartwatch misses the mark - CNET

Polar M400 Fitness Tracker New!!! - electronics - by owner - sale - craigslist

Polar M400 GPS & Activity Tracker Watch In-Depth Review

A few quick thoughts on Fitbit's new activity trackers, GPS watch (with optical heart rate!)

Polar M400: Running and activity tracking in one (pictures) - CNET

Polar M400: An activity tracker with the heart of a GPS running watch - Video - CNET