Notes: "The Sans & Streiffe Model 311 is a re-branded version of the Relay/Ricoh Model 150. Relay/Ricoh slide rules were sold under many brand names around the world; one estimate puts the number of brands at 27. Relay and Ricoh were the brand names used by the manufacturer; all the others, including SIC, Lafayette, Jason, Compass, Lutz, Alvin, Micronta, etc., were OEMs. The Model 150, or S&S 311, was their basic log-log engineering slide rule."
