This project is basically a volume pedal in a box with knob control. It can be a very handy box to have around, and contrary to popular belief, it can fix impedance mismatches between stompboxes (e.g. Fuzz Face & Wah) that a buffer cannot fix (buffer lowers impedance, this essentially raises impedance). It can also be used in various other lineups where a set volume reduction is needed. Electro-Harmonix had a similar pedal out in the past called “Signal Pad”

Description from General Guitar Gadgets.