I bought an Alesis Photon x25 midi controller, the one with the light-beam controller that responds to the position of your (left) hand…
This one was described as “grotty”, with a couple of missing knobs, a dodgy security sticker, and decades of dirt and smeg.
I’ve cleaned it up, but ran into trouble finding replacement knobs..
Alesis directed me to a seller of second-hand spares, who wanted $33 for one black knob. No-one has the clear “volume” knob.
I ended up buying 11 black control knobs from CPC. (ordered) to replace ALL the black knobs AND the white one..
Should be a nice unusual controller.. for £25 all-in.