Hi. There were three dual gauge projectors called FP-A, FP-B and FP-C made from 1967-1969. Their design was similar to the original FP. The FP-A was most expensive, and came with a fitted zoom of 20-32mm. It was 65 UK pounds compared to 55 for the FP-C. 10 UK pounds would have been a lot of money in the late sixties. The main difference seems to have been the lens. The FP-C had the 20mm with the option of a converter. I don't know about the B model, but all FPs were gone by 1969, and replaced by the Brilliant model. I think the old FP for Standard gauge had the removable barrel also to accommodate a converter, but possibly of different dimensions. I still use my FP to project my sStandard 8 films from a few years ago. It is a great machine, although I am still looking for a Bolex 18-5.... Alex