Nikon D300 User Manual page 694

to the currently stored White balance. If you change your
mind, return the little black square to the center of the
color box. You'll see the color mired values changing on
the right side of the screen in the fields next to A-B and
G-M. Each increment (click) of the Mutli Selector is
equal to about 5 mired.
5. Press the OK button to save your adjustments to the
stored White balance.
694