Where can I find the serial number of my Polar device?

Applies to: A300, A360, A370, Cadence sensor Bluetooth® Smart, Grit X, H1 heart rate sensor, H10 heart rate sensor, H2 heart rate sensor, H3 heart rate sensor, H6 heart rate sensor, H7 heart rate sensor, H9 heart rate sensor, Ignite, M200, M400, M430, M450, M460, M600, OH1, Polar Balance, Polar Loop 2, Polar Loop Crystal, Speed sensor Bluetooth® Smart, Stride sensor Bluetooth® Smart, V650, V800, Vantage M, Vantage V, Vantage V Titan

Polar A300	Polar Loop 2, Polar Loop Crystal, Polar Loop (Misty Blue)
Polar A360/A370	Polar Loop (Smoky Black and Blackcurrant)
Polar M400/M430	Polar V800
Polar M600	Polar M200
Polar M450/M460	Polar OH1 optical heart rate sensor
Polar H9/H10 heart rate sensor	Polar H7 heart rate sensor
Polar H6 heart rate sensor	Polar H1, H2 and H3 heart rate sensors
Polar CadenceSensor Bluetooth® Smart	Polar Speed Sensor Bluetooth® Smart
Polar Stride Sensor Bluetooth® Smart	Polar Balance
Polar V650
Open the back cover to find the serial number.
Polar Vantage V	Polar Vantage M
Polar Ignite	Polar Grit X