Click here for more shots via this auction. If you know more about this unit, feel free to comment.
Details
"VARIABLE Hi-CUT and LO-CUT RACKMOUNT FILTER. It is hard to find much info out there about these, but I did see that recording artist John Vanderslice mentioned incorporating a similar, less feature packed Allison Labs filter into his recording setup. This is a passive unit, requiring no power cord, and all connections and controls are positioned around front. This unit IS VERY HEAVY, and VERY STURDY- extremely well made."
