Dunlop positioned the M196-U MXR A/B Box as a signal-routing utility pedal within the MXR effects line. Its function was to split an instrument's signal between two separate output amplifier paths, with a dedicated Thru jack intended to feed a tuner or any other device requiring a constant, uninterrupted signal.

The unit ran on DC 9-volt power and drew 1.4 mA, placing it among the more power-frugal pedals in a typical signal chain. Switching was handled by true hardwire circuitry, meaning the signal path was completed by a direct mechanical connection rather than a buffered or relay-based circuit — a characteristic that mattered to owners concerned about signal transparency when the pedal was engaged.

Owners working on routing configurations or needing to trace a fault in the switching or jack connections should consult a qualified guitar technician familiar with effects pedal circuitry.