adjusting standard Ultima speedo

[XTR2Turbo]

I want to adjust my speedo slightly but don't have the instructions. It is a standard White faced Ultima unit.

Please could someone explain how this is done. I understand there is a number entered but can't see how this is done.

Thanks

David

[GtrSimon]

Hold the button down while turning on the ignition, the scroll through the numbers, when done wait for it to reset

[XTR2Turbo]

thanks I'll give that a go

David