Artists use this
Its a footswitch!!!
Nice vintage footswitch. Acti and Desacti ( vate ) Tremollo and reverb ( you can use both effects at the same time , or not ) only usable for trully vintage amps ( mine is a 1970 Pro Reverb Silverface so, it came with it ) THATS IT!!! Bye bye, go play your vintage amp, :)