About Altitude Calibration - Halfords Bicycle Computer Owner's Manual

8. About Altitude
Tip for Quick Altitude Calibration
1. Press both A and B buttons for 1 second, and the current
altitude value will return to zero.
2. Press the A button to set the value of a digit, and press the B
button to move to the next digit.
3. Attention: Calibrate the current altitude only when
there're no speed signals.
Calibration:
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