Danbury, CT: Amphenol RF Division 1969. Brightr orange printed 9 x 11 inch folder containing instructions and a nearly 9 inch two sided large plastic and paper circular slide rule/volvelle tucked into the rear pocket. Minor soiling to the folder, bright and clean internally. Near Fine. various. 
Before electronic calculators, many specialty calculations that were done repetitively were put on slide rules to reduce human error and speed up work processes. This folder includes instructions for Radio Transmission Line Calculator, and the slide rule. The rear inside folder cover is an expanded scale smith chart. Not often found in this condition, and a scarce circular slide rule for those who collect calculating devices. These were never widely circulated, and would only have been used by serious communications engineers and system designers. Their survival rate is small given the construction of the device.
"Amphenol RF Division specializes in the design and manufacture of RF and microwave devices. Specifically, coaxial connectors, coaxial switches and microwave components and assemblies for systems applications."
"The Calculator relates the series components of impedance at any position along an open-wire or coaxial transmission line to (1) the impedance of any other point, (2) the standing wave amplitude ration (S W R), and (3) the attenuation...."