Elecom M-XGS30BB User Manual page 21

3) Put the battery cover back on.
4) Slide the power switch on the underside of the product to the ON position.
The LED will light up for a period of time.
* When the battery level is running low, the LED will blink for a period of time.
Power-saving mode
When the mouse is left untouched for a fixed period of time while the power is ON, it
automatically shifts to power-saving mode.
The mouse returns from power-saving mode when it is moved.
* Mouse operation may be unstable for 2-3 seconds after returning from the power-saving mode.
Replacing the battery...