Tascam M-1016 Knob and push button
The 1016 was a bit cramped so they used some different size knobs push buttons so I have listed them here by the model number, some may well be common else where but people search by model
I have a slider/fader cap size 22.81mm long 10.19 mm wide tang outside diameter 8.03 width 3.2mm it protudes above teh cap about 2 mm, see photo for details
I have a pushbutton 15.2mm long by 6.36 square at widest part, see base photo to see if it matches yours or others.
both in two colours