a good flux which was on offer at time of purchase works really well but make sure you clean copper and fittings before applying to get a good soldered joint.
Just great product that works as it should. No issues
It had good reviews and my current flux was getting low so it has been purchased ready for use - not much more I can say until the old one runs out!
Looks good so far, havent had a chance to use it yet
I have always used la Co flux never had a problem with it excellent wouldn’t use any other type
As a professional, wouldnt use any other make.