Imitation really is the sincerest form of flattery - not far from an FSQ-106ED clone
Skywatcher did originally make these as quads, but had coillimation woes, so redesigned them as triplets with seperate flattener. A few quads escaped into circulation and are collector's items now (though plagued with issues).
Do watch for diffraction spikes in the images - the split rubber rings SW use for the lens cells have been shown on occasion to impinge into the light path and create diffraction spikes (smallish). A company in Germany offers to fix the issue for a small cost, IF you have the issue:
http://interferometrie.blogspot.com....-esprit80.html