Vol. for 1955 includes an issue with title Product design handbook issue; 1956, Product design digest issue; 1957, Design digest issue.Carries specifications, characteristics and dimensions. ... contact arrangement diagram, operating character. istics and electrical rating of switch with built in indicating lamp. ... Describes functions in controlling mechani. cally held contactors and low-voltage relays, illustrating with wiring ... It provides a relatively pulseless flow: volumetric and mechanical efficiencies are high; it is balanced and quiet inanbsp;...