I have a DeVere 5108 8x10 enlarger with the color head. I was given both the 8x10 and 5x5 mixing boxes with the enlarger when I bought it a year ago, but now that I have it set up, I was reading through the manual looking for the code for the correct light bulb and I saw that for this head, there is supposed to be a special mixing box for use with a 240mm lens. I have 240mm and 300mm lenses, but I don't know which box I have. KHB Photographix site is not linking to the DeVere section for me to see if they have a third box listed. Anyone know if there really is such a thing and how to tell if the one I have is for 240mm or 300mm lenses?