Reporting question for Knob - Marshall, Brown, Gold Cap, Push-On, Single

Product:
Knob - Marshall, Brown, Gold Cap, Push-On, Single

Question:
I’m looking for a replacement knob for the drive potentiometer on a Marshall 3210 mosfet lead 100 head. The shaft is solid and acts as a push/pull for added gain. None of the other knobs on the smoke fit. What should I be looking for?