The weapon was invented when Juan Lehnar put together the very first SMG to be devised in South America. It was a selective-fire weapon chambered in the 9mm Parabellum round fed by a curved magazine inserted on the left side of the receiver (the magazine well could be turned upwards to make the gun flatter, for transport). It had an underfolding stock reducing the length from 700mm/27.5″ to 290mm/11.75″, and the wood foregrip could be moved to lie flat under the forward end of the receiver. A single prototype was built.