wrote:

That's strange that Europeans use a half-metric half-what-you-call-Imperial
standard of units.

Not necessarily the rest of Europe but the UK.

Do the Germans and French also use "inch" sizes for their ratchets?

We only say gallons BUT when talking to the ex-colonies we have to say
'Imperial' because your pints and gallons are different from ours.

1 imperial (UK) pint = 1.2 US pint
1 imperial (UK) gallon = 1.2 US gallons

I see. Like you, we only speak of "gallons", where we don't ever need to
distinguish between your gallons and our gallons, I guess.