Polar M400 – Battery Life, Performance and Verdict Review

GPS fitness band and heart-rate tracker that's currently unbeatable for budget and size
GPS fitness band and heart-rate tracker that's currently unbeatable for budget and size

Polar M400 Review: Fitness/Sleep Tracker Watch With GPS

Polar M400 Review Tested by GearLab

Polar M400 with Heart Rate Monitor (Black) : : Sports, Fitness & Outdoors

Tech Review: Polar M400 GPS Running Watch - That Shelf

the Polar Pacer Pro Review - For Runners ? Good for Triathletes too

Polar M400 GPS & Activity Tracker Watch In-Depth Review

Polar M400 GPS & Activity Tracker Watch In-Depth Review

Polar M400 Review

Tech Review: Polar M400 GPS Running Watch - That Shelf