2 BUTTON FOOTSWITCH FOR SUPRO AMPS! The Supro Dual Footswitch allows players to control the Tremolo, Reverb, Drive, Boost, and channel-switching circuits of any Supro amplifier with ease. Connecting via a 1/4" TRS cable, the Supro Dual Footswitch allows you to turn on and off your onboard amp effects without having to alter tone controls.