This expression pedal, built by Mission Engineering, is specifically designed to work with the Mastermind, Mastermind GT, Mastermind LT and Mastermind PBC. On the Mastermind, it will work as a standard expression pedal. Connecting to the original Mastermind controller requires one 1/4-inch TRS cable (not included) On the Mastermind GT, LT and PBC, you can use both the expression pedal function and the toe switch. The toe switch will work as an additional button on the Mastermind GT, LT or PBC, and it can be assigned to send multiple MIDI messages, just like the GT, LT or PBC's own buttons. The toe switch has a status LED that displays the current state of the function it's controlling. Please note that, when using both the expression pedal and toe switch, you will need to connect this pedal to your controller using two 1/4-inch TRS cables. One connects to the expression pedal connector on the controller, and the other to the external switch connector. (TRS cables are not included with the purchase of this pedal).