The switch to the “Small Box” RAT was essentially just a cosmetic makeover. While the circuit remained the same, the enclosure evolved into a more compact version, with a 12-gauge U-shaped base. The Pro Co logo sat next to the RAT logo on the pedal top, silk-screened in black inside of a white box. In 1986, the logo was reversed to white on the black, painted metal.
text from Pro Co website
09/27/2020: ToneHome is looking for an Ibanez CS-505 narrow box first issue with flying fingers side graphic. Any hint is highly appreciated. Other than that we're looking for an Ibanez AD3000 Professional Analog Delay & Multi Flanger and an Ibanez OD-850 narrow box (v2-v5) either boxed or just the empty original box. Please submit your offers or leads here: e-mail