Historical
NEMA ANSI C78.1430:1997
Electric lamps - slide projector lamps, condensing, dichroic, 1.65 inch (42mm) integral reflector, rim reference tungsten- halogen lamps with gx 5.3 bases
Defines the dimensional limits and other physical characteristics required to ensure commonality and interchangeability and to assist in the proper application of projection lamps.
NEMA: National Electrical Manufacturers Association [nema]