Genuine Soundcraft caps that were removed from the EPM mixers (if I remember correctly)
They are probably the same on the EFX and many others
For years Soundcraft used T bar sliders but has changed to more simpler pots, looks like a standard 4mm one, have taken photos front and back so you can see the mounting
They maybe a new standard on all the new small Soundcraft mixers
As I get more information i will add it here
Only have a few as its a new item
I have not seen a violet one on the EFM so please check all just in case i made an error , rest of colours line up