|The US Vox V1081 and 1084 solid state Berkeley II and Berkeley III included this accessory three button foot pedal. This pedal controlled reverb, tremolo and MRB (mid range boost).
The MRB foot switch is unique in that it does not have a latching mechanism. It is a "momentary" style switch. One must hold the button down to engage the effect. When you release the button, MRB is turned off.
North Coast Music offers the exact replacement switch mechanisms, cable, six pin connector plugs, V1081 and V1083 Berkeley Reverb wiring schematics, and even the special spanner style nut used to secure the switches. Click here to go to the web page in the North Coast Music web site that offers this foot pedal and replacement parts.