Polar M400 GPS Sports Watch without Heart Rate Monitor, Black : Amazon.ca: Electronics
Polar m400: So geht der Reset - CHIP
PolarGlobal on Twitter: "@MarcDeuter Hi Marc. Please make a factory reset to your M400. It should help. https://t.co/10CJRbb185 If still issues, your local Polar helps at https://t.co/k9QIKDpdCT" / Twitter
How to do a hard reset on POLAR A370? - HardReset.info
How to Factory Reset a Polar M200 Fitness Tracker - Support.com TechSolutions