A button

Pressing this button in any mode cycles between displays.

While a setting screen is displayed, pressing this button scrolls available menu items upwards.

B button

Press to turn on illumination.

C button

In the Timekeeping Mode, pressing this button enters the Training Mode.

Pressing this button while any mode’s setting screen is displayed applies all of the screen’s pending settings or changes.

D button

Hold down this button for at least one second to return to the Timekeeping Mode. Pressing this button while a run timing operation is in progress returns to the run timing screen.

Pressing this button while a setting screen is displayed scrolls available menu items downwards.

E button

In other modes, pressing this button returns to the Timekeeping Mode.

While configuring settings, pressing this button goes back to the previous screen.

 Optical sensor (heart rate detection)

Detects your pulse for heart rate measurement.

 Charging terminal

Plug in the charger cable here to connect to a device with a USB terminal for charging.