Historical
ANSI C78.1407-2004 (R2015)
Electric Lamps - Condenser-Reflector, Four-Pin Prefocus-Base Projection Lamps - Dimensions
Specifies the dimensions essential to the interchangeability of condenser-reflector lamps having four-pin prefocus bases, T12 or T14 bulbs, and used in 8mm motion-picture projectors.
NEMA: National Electrical Manufacturers Association [nema]