Sebastian_G wrote:
They work very well (for imperial and metric ;-)
As a german, you will go to hell for this. If you rather fancy a few hundred years in purgatory instead, use this:
There is an"ultimate" universal wrench but I can’t find it with a quick search. It looks a bit like pliers but the jaws have various 60 degree cutouts and tighten around the nut. I have one that goes up to about 12mm and one a bit larger. I bought them both in Japan (Tokyu Hands – a don’t miss destination if you’re in Tokyo) but they’re made in the US.
Metrinch and the other?
Not bad if you are happy with mangling the nut a bit 
As a german, you will go to hell for this. If you rather fancy a few hundred years in purgatory instead, use this:
https://www.hazet.de/de/produkte/handwerkzeuge/schraubenschluessel/einmaulschluessel/3621/einmaulschluessel-verstellbar?number=279-18
The Knipex tool is much superior. With this type you will always have some play between the tool and the nut. But the Knipex tool will squeeze the nut while both surfaces stay completely parallel which does no damage to the nut while nearly all the other tools will somehow bite into it and damage it badly. In fact it might be even better than a fixed size 2 side spanner as that will also have some minimal play. I really recommend trying it. For decades I had no good opinion about all those ajdustable tools for hex nuts but that Knipex tool really is different.
Here is a video which shows it in operation:
I agree re this tool. I have it too. It is not cheap but is excellent.
However, if you need something strong, or access is not great, then you can’t beat a proper spanner, and better still a socket.
Sebastian_G wrote:
For on the road after a recommendation from Ultranomad I purchased 2 of this type:
Knipex
Excellent. I’ll buy one at once!
Yes, that’s right, you only realize that you actually need more valuable tools when you messed up a few important screws, however for some occasions the Walmart stuff is ok
Anybody experience with Metrinch?
Nope.
Short of buying additional tooling as pointed to in some of the posts above, I’ll stay with my tools of predilection. Those work as well for metric as imperial sizes, guaranteed.
