I'm having the hardest time finding the correct footswitch for my amp. I have and old Peavy Studio Pro 112 combo (Red Stripe) and it has a remote switch jack in the back. I've found two that I think are the right one but I'm not 100% sure and I want to be sure before buying one.
The switch is for switching channels and turning on and off the reverb. This is a fairly common configuration on dual channel with reverb amps.
The foot-switch uses a TRS (Tip Ring Sleeve) connector to a two switch box. The connector uses Tip/Sleeve for one switch and Ring/Sleeve for the other switch.
There are generic dual foot-switches that you can buy for replacement for this setup. Other Amp brand's foot-switches can also work if you are looking on the used market. I personally use an old Crate dual switch pedal on my new VHT.
The switch box itself will most likely contain two latching footswitches. One for reverb and the other for changing channels.
It's not difficult to check with most amps which connections do what. Using a TRS (stereo) 1/4" jack with three short wires attached, touch two of them together and see what happens. Shorting the Tip and Sleeve will switch one function, shorting Ring and Sleeve will operate the other. That established, most likely any double footswitch for an amp will function. It may be that the two buttons are reversed - change the labels, or leave them - it's a 50:50.