26 Billy Zoom 6 months ago You can wire them so they cut bass in one position and cut treble in the other position. It's a useful mod. A stock mud switch is wired so that one position is like turning a tone pot part way down, and the other position is like turning the tone pot all the way down. It was supposed to make tone changes quicker and easier on the fly, instead of trying to find the sweet spot on a tone knob. FWIW, Chet removed the mud switch and added a tone pot in place of the neck pickup volume control.