I'm not really sure exactly what this for I've seen things like this before with a Kodak carousels the ectographs I'm not really sure if that's the same thing I just couldn't find any of the KimChuk dissolve controls other than some auto fade switches but nothing with a foot control nothing that is model OHP-1 and most of the stuff that this guy had was fairly rare it didn't look like it's ever been out of the box or used so we bought it set it aside for 25 years and now we have it so if you know exactly what it is please message me let me know if you have any questions do not hesitate to message either thanks for looking and enjoy