Er... I think you'll find that's Holland, USA
And they are calibrated un USG.
You can calibrate the universal version in whichever unit you prefer. But it isn't much fun, the realities of it are that you should drain all fuel to the unusable level and then add it back in increments
If you didn't start with a full load then you'll have to go and fetch some more. Try finding a friendly pump person with plenty of time
