Simple and robust: the Orange FS-2 Footswitch is ruggedly built and connect to your amplifier via any standard instrument cable. The FS-2 is compatible with: 

CRUSH 20 CRUSH 20RT & CRUSH 35RT (CHANNEL)
CRUSH PRO SERIES (CHANNEL OR REVERB)
TH30 AND TH100 (CHANNEL)
DUAL TERROR (CHANNEL)
AD30 (CHANNEL)
OR 50 (MASTER VOLUME DEFEAT)
CUSTOM SHOP 50 (EQ LIFT NOTE: THE LED WILL NOT ILLUMINATE AS THE CUSTOM SHOP USES PASSIVE SWITCHING CIRCUITRY)
ROCKERVERB (REVERB OR CHANNEL)
DUAL DARK (CHANNEL OR ATTENUATOR)
OB1-300 & OB1-500 (BLEND CONTROL)
CRUSH PRO SERIES (CHANNEL & REVERB)
ROCKERVERB (2 FUNCTIONS: CHANNEL OR REVERB OR ATTENUATOR (MKIII))
THUNDERVERB (REVERB & CHANNEL)
DUAL DARK (CHANNEL & ATTENUATOR)