Lamps of this type are quite similar to those of Loeschcke type I, the major difference being their rounded rather than angular-tipped volute-nozzle. Substantial volute-spines often decorate the nozzle, which is smaller in earlier examples and tends to be larger in later ones. In that case the broader volutes seem to be compressed between the nozzle and the discus. Practically absent in the Augustan fort at Haltern (probably abandoned in A.D. 9), the main production of the type began rather later than that of Loeschcke type I A. Only a few lamps can be regarded as Augustan, primarily ones whose shoulders are decorated with rills. Some of the latest examples bear tria nomina signatures; production of the type ceased in the first third of the second century A.D.
The shapes of the body, shoulder, and base recall those described above in Loeschcke type I. Flat shoulder forms (Loeschcke I to IV) do exist, but the rounded shoulder forms V to VII are in the majority. Only four of the Getty lamps have a handle—three Augustan examples, cats. 163–65, and a lamp of an odd type with side-lugs, cat. 242. Base-rings are found, but the majority of the lamps have a flat base marked off by a circular groove. Loeschcke type IV corresponds to Bailey type B, divided into five groups, each of which will be briefly introduced below. Similar to Loeschcke type I and nearly contemporaneous with it, this type was diffused to all parts of the Roman Empire, through either export or local imitation.
Since the Getty lamps lack archaeological context information, the dates given follow those of other publications, mainly Bailey BM II. Out of eighty-two lamps of Loeschcke type IV, twenty-eight have a given eastern place of manufacture or origin; forty-four an African, two an Egyptian, and two a German; the place of manufacture or origin of the six remaining ones is unknown.