Early "shadow logo" version of the FX57 in very clean condition. Includes battery compartment cover! Also, the original box, instruction manual, warranty card, and a contemporaneous DOD catalog. Box has duck tape residue on the top but the instructions are in great shape and informative!
Description from the manual:
'The FX 57 is very high gain preamplifier that is overdriven to produce a distorting of the input signal and help sustain the notes longer. These effects simulate the characteristic distortion of a guitar amplifier turned up so high that it "clips" the signal, distorting it. The FX 57 offers a unique distortion circuit with a built-in delay of 7 to 40 milliseconds for a distinctive thickening of the distortion effect for use in rock distortion sounds. The FX 57 Hard Rock Distortion makes its distortion effect sound at any amplifier loudness setting and also sustains your guitar notes.'
Note: advertisement is for reference only and is not included