The feature-packed and waterproof Polar M400 offers a good set of features for beginners and advanced runners a like. It also provides feedback on your daily activities and sleep.
Polar M400 Review Tested by GearLab
Polar M400 review: Polar M400, an activity tracker with the heart of a GPS running watch - CNET
Polar M400 GPS & Activity Tracker Watch In-Depth Review
Polar M400 GPS & Activity Tracker Watch In-Depth Review
Polar M400 GPS & Activity Tracker Watch In-Depth Review
Polar M400 GPS Watch Review (Best Running Watch)
Polar M400 GPS & Activity Tracker Watch In-Depth Review
Polar M400 GPS & Activity Tracker Watch In-Depth Review
Best Buy: Polar M400 GPS Watch with Heart Rate Black 90051339
Polar M400 review: A feature-packed GPS running watch that can also track your steps and sleep - 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
Polar M400 Review, Detailed, Discount Links
Tech Review: Polar M400 GPS Running Watch - That Shelf