I have wanted make the cable on my AKG 271 mk.2 longer, and I have used a 6mm (diam.) mic cable, but it always bothered me, it was too clunky and heavy.
So I bought 10 meters of this to try it out.
It's a little fiddly to make the transition smooth using heatshrink tubing, but it can be done if you plan the procedure ;-)
I ended making it 6 m. longer and am very pleased.
I wish AKG just would offer longer cables (they are snap on already), but this works fine, and the cable is easy to work with.