I ordered some PA stands from Thomann back in 2009 and one of the knobs arrived cracked, so I contacted Thomann and they sent me this replacement knob right away.
I know there's not a lot you can say about a knob but it's actually really well designed. As it's not circular and more like a soft triangular shape it makes gripping it very easy - you can get a lot of torque out of it so tightening, and more importantly - loosening, is a lot easier than with the equivalent circular type.
Anyway, if you're looking for a knob you won't go far wrong with this one.