I just bought a 23cii, and it arrived with a 35mm diffuser and one I've never seen before. It's just like the 35mm one, only, er, bigger. It fits perfectly in the condenser housing. I thought it might be a 2 1/4 diffuser, but I checked the manual and did an online search, and didn't find anything. Could it perhaps be a *color* diffuser, as used with the dual dichro head? If this is the case, can I use it with the 75w lamp designed for the condenser head, or will the light be too dim? My other source of puzzlement is what seem to be handles protruding from the bottom of the lamp house. There are two of them, with screws to hold them in - the screws themselves bed into what appears to be white plastic. The manual and exploded parts diagram don't refer to them. Does anyone know their purpose? I was afraid to just unscrew around, in case I damaged something. Sorry if these are silly questions, but I have looked about and tried to find answers, without any luck. Thanks for the help.