I bought a used doubler from a guy here in Arizona, He said it is a first generation. I have not dissassembled it yet. This unit has an aluminum plate behind the 203, another smaller aluminum plate behind that, and then a 205 adapter in front of the NP205. It does not look like the first generation doublers I recall seeing. I was wondering what the differences were if any on the 203 output/205 input, between the 1st gen, and the current model.