Toronto. The summer of 2019, I did a post on an Italian knock-off of a focussing slide viewer. The Al Who [L WHOO] mentioned in the above link was the code name for a Leitz 30x magnifier designed for the focusing slide.
As noted about five years ago, the San Giorgio company in Genoa made a short lived Leica copy and accessories. Time and the short period of marketing these products make them very scarce today.
Looking at the viewer, the construction quality is very much Leitz-like and a tribute to the famous maker. The Italian camera and accessories were all post-war, sold for those few years before the Famous M-series of bayonet mount Leicas took over from the original screw-mount gear. This change likely contributed to the demise of San Giorgio copies – that and the snobbery for German made Leicas.
It should be noted, that such high power magnifiers focussed on the arial view. The focussing slides had a clear glass spot in the centre of the ground glass.