Sunset Resistance Dimmers (1945)
Strand

Type D Sunset Dimmer (1953)

Type A, Type A1, Type B, Type D, Wall Mounting Type
Type D: Developed for systems where the loads are in excess of the maximum for Type A.1 dimmer.
Wall-Mounting Sunset Type: self-contained dimmer unit suitable for use on theatre auditorium or decorative lighting in lecture halls, churches etc or for master dimming on small stages.