Casio WSD-F20X User Manual page 62

While the " 2 Layers
If you do not perform any operation on the watch, the unlined screen shown
in ② will be displayed. Tapping the touch screen will switch to the color
display.
While "Always-on screen" is OFF
If you do not perform any operation on the watch, the unlined screen shown
in ② will be displayed. Tapping the touch screen will switch to the color
display.
"Always-on screen" is a Wear OS by Google setting item. For details, visit the
website below.
https://support.google.com/wearos/
TOOL App Monochrome Display
Holding down the TOOL button for about three seconds while a TOOL app
color display is shown will switch to a simple monochrome display.
Tapping the touch screen while the monochrome display is shown will
●
switch to the color display.
For information about the TOOL app, see
●
" watch face is selected
EN-61
"Using the TOOL App".