Working on a 1965 euro 230, with a very odd part in the engine compartment. At first I thought it was an aftermarket fuel filter, but then I noticed that it had the remnants of electrical connections. It turns out that it is a FIAMM Roadmaster compressor for an air horn setup. The hose fits over the nipple and runs to the horns, and the red fitting is where a special oil is added. There is a very official-looking hole in the radio plate that I suspect was for a button to activate the compressor and honk the horn.
High-end stuff, used on Ferraris and Porsches back in the day.
What I found most interesting is the bracket. That is a serious piece and makes me think that there was an install kit for the 113 unless someone went to a lot of trouble for this particular car.
Cheers,