Will not work for HymerCar. Too big square opening, sticking out of car profile too much and I was not able to move the big ball valve with such a small key.

Will not work for HymerCar. Too big square opening, sticking out of car profile too much and I was not able to move the big ball valve with such a small key.
@MichalK It won’t work sorry it’s designed for a Dethleffs Trend Motorhome, even with other styles of Dethleffs they are sized differently, have you tried a radiator key maybe ?