Ruby XL HD User Manual page 36

Press and HOLD the green/yellow button
2.
yellow PLUS button
increase or decrease the distance between the masks.
To remove reading masks from the screen, press and HOLD the
3.
green/yellow button
buttons (
30
(2) or the yellow MINUS button
(1) and then press and HOLD both yellow
and (2 and 3)).
(1) and then press the
(3) to