2nd Production Version Big Box Rat
Filter Control - Highs are now decreased when turned clockwise also using Log Taper pot
Pro Co Sound Logo with "Sound Inc" vertically on side
Now using only Electrolytic caps for larger values.
Rat logo now using lower case "a & t"
Knobs are now what will be the standard up until mid 2000's
Distortion, Tone, & Volume labels closer to top edge of pedal than Ver. 1.
No battery door on bottom
1981 Filter Rat