From Rank Strand Electric Stage Lighting Brochure, 1975

These compact desks, for use with permanently installed STM Thyristor dimmer racks, provide the essential facilities for presetting precise intensity levels in advance of the lighting in use and master faders to change from one effect to the next.
They have the great merit of being so easy to comprehend that no particular know-how or technique is required for either plotting or operation, an important factor in multiple-user situations such as a multi-purpose hall.
The two preset desks are for table-top mounting but the 15" angled operational area is removable for access and reversible within the enclosure if wall-mounting is required. Control cable entry is through the right-hand end when table-top mounted.

3 preset desk for 40 control channels is a floor-mounting near-vertical wing panel suitable for a seated or standing operator. Rear access is required for initial connection of the control cables to the two 20-dimmer racks, and for subsequent inspection. Control cable entry is within the thickness of either of the two legs.