This derailleur is a nasty piece of work. The gauge of steel used throughout is too thin for the job and has bent in a thousand places, the plating has a terminal dose of leprosy and every opportunity to lack precision has been grasped with both hands. I kept looking at my photo thinking that it was out of focus - it wasn’t, that’s how the derailleur really is.
Perhaps out of embarrassment at its shortcomings, there is no branding on any of the plates or even on the pulley wheels. Three of the bolt heads are branded as ‘MELFRA’ - but my suspicion is that this may be a brand of bolts rather than of derailleurs. The internet reveals that a company called ‘Industria de Parafusos MELFRA Ltda’ exists to this day in Sao Paolo supplying basic steel products like bolts.
Despite all this criticism, this is an original derailleur design, and it has some virtues - in particular the placing of the adjustment screws is remarkably convenient for a ‘flat plate’ based derailleur. In this respect, it has more in common with a Shimano Pecker than with a Huret Svelto.
This ‘1st style’ has an adjustable cable outer stop, and interestingly shaped cable clamp washer and an unusual arrangement for restricting the movement at the hanger plate - in this respect resembling a Sachs Super Sport.