Schnell Penselpen combos are uncommon and desirable. I've seen quite a few over the years, but when this example turned up, I couldn't recall having seen another in metal (celluloid is the norm). This one is unquestionably correct and original: the barrel opening is made specifically to accommodate the distinctive Schnell slide filler, whose internal retaining ring is soldered in place inside the barrel. The nib is Schnell, as is the feed.
Yet pretty much everything else isn't uniquely Schnell at all. Examined as a whole, the pen clearly came out of the same factory as the metal lever-filler combos most often found branded as Hicks, Edward Todd, and Twinpoint. While the cap threading sometimes varies from brand to brand, the pencil ends are identical and can freely be swapped, while the section profile is distinctive as is the internal construction, with both lever pivots and pressure bar assemblies soldered in place.
The differing thread profiles are visible in the detail above. Interestingly, the longer section is on the shorter ringtop combo, rather than on the slightly longer Edward Todd, which has a clip.
The metal content markings typically use the same block capital lettering, too, along with the unusual use of "PLATE" instead of "GOLD FILLED" or "G.F."
Although proof is still lacking, the likelihood is that Hicks was the actual maker of this group of combos.
ADDENDUM: One of our correspondents formerly owned a similar Schnell in the full-length version with clip. Whether any were made in solid gold or sterling silver remains to be seen.