Warwick Potentiometer Dome Knob Black

The only thing I have to criticize is some kind of dullness the black poti knobs have, when first unpacked. I bought a lot of those knobs (single and tandem) and got the same strange "patina".
Using a microfleece to clean them up helps, though.
I've got lot of bass guitars and into three of them, I installed Glockenklang 3-band electronics. Since I don't like too many poti knobs, I'm using the stacked ones. Exactly for that purpose, these tandem knobs work absolutely fine. On my Warwick $$5, you really can't say if the bass didn't have that tandem-knob right from the start ;-)
Mounting is no problem, all you need is a small allan wrench (older models need a normal screw driver) and you are set. Pro tip: Use a sheet of paper, fold it 3-4 times and lay it on your bass before you mount the knobs, touching the poti axis. This way you ensure there's a minimal gap between knob and body to leave it moving freely.