Lamps of this type are characterized by a rounded body, ribbon handle, and, in most cases, one side-lug—a lingering characteristic of Hellenistic lamps. The shoulder and often the lower sides of the basin are decorated with rows of closely spaced globules (Warzen, warts), hence the appellation Warzenlampe. The flat-topped nozzle is long, with beveled sides and a splayed end terminating in two blunt obtuse angles. The concave discus may be decorated with one or several rings. The base-ring often bears a workshop mark consisting of a letter (most often N or R) or various combinations of impressed points. The production originated in central Italy about 70 B.C. and was soon diffused mainly to Gaul, Spain, the Italian isles, and Africa. When first produced, the lamps were covered with black slip or glaze, which by 50 B.C. was progressively replaced by a red one. The production lasted to the end of the reign of Augustus.