Made these a couple of months ago when I was a bit shy on the minimum charge to have some urgent lazer cutting to do.
Here is SA we have 15mm and 22mm general domestic water pipes.
It turned out my shifters were just to small to grab the 22mm fixtures.
So I drew up spanners that will fit these connectors. I added a lip on the open side of the spanner as I found a couple of occasions I needed to have the spanner stay on the nut while I move the other spanner to the next flat. Can always cut it off at a later stage if it is more trouble than worth.
I had them cut from 3mm mild steel with a double plate on the mouth side to add a bit of strength and not have the spanner too heavy. I created more leaks by over tightening these type of connectors than having them too loose and not squashing the ferril.
Here they are in bright pink as
1) I will not loose them and
2) That was the only bright paint I had on the rack (after the last project I helped the little grand daughter with)
I can upload drawings if you use the same type of plumbing connectors.