Hopefully a simple Mamiya C330 question

I love my C330 but i have 1 question that has nothing to do with the camera's function. On the left side, on the knob that locks & unlocks, what do the symbols mean in the little window to the left of the ASA reminder? I can't seem to find that info anywhere.

Thank you,

Craig

According to Graham Patterson's page (Dead Link Removed) it is a reminder for the type of film (colour, b&w, tungsten).