Apple PowerBook (Duo 270C) - Manual (Page 40)

n
If you prefer, you can adjust the angle of the keyboard by
rotating the elevation feet at both ends of the back panel until
they snap into position.
The back of the keyboard is slightly elevated when the feet are
in use. Otherwise, the keyboard is level.
Mouse
n
If you use a mouse, position the mouse at the same height as
your keyboard. Allow adequate space to use the mouse
comfortably.
Built-in display
n
Adjust the angle of the display to minimize glare and
reflections from overhead lights and windows.
n
If your display screen has manual brightness and contrast
controls, you may need to adjust the brightness and contrast
of the screen when you take the computer from one work
location to another, or if the lighting in your work area
changes.
Brightness
Contrast
24 Chapter 1: Setting Up Your PowerBook Duo