Polar no longer makes the M400. We reviewed a deep field of well-designed devices. As smartwatches merge with GPS watches and then absorb activity
Polar M400 GPS Sports Watch without Heart Rate Monitor, Black : : Electronics
Polar M400 Review
Polar M400 Review - , Running tips
Polar M400 GPS Sports Watch without Heart Rate Monitor, Black : : Electronics
Polar M400 GPS Running Sports Watch With Heart Rate Monitor (Pink) : : Electronics
Polar M400 GPS Running Sports Watch With Heart Rate Monitor (Pink) : : Electronics
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Polar M400 GPS Sports Watch without Heart Rate Monitor, Black : : Electronics
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Polar M400 GPS Smart Sports Watch with Heart Rate Monitor (Pink) : Sports & Outdoors
Polar M400 review: A feature-packed GPS running watch that can also track your steps and sleep - CNET