Notes: "Sometime in the mid-60s SIC produced this two-sided advertising poster, which doubled as a catalog of their slide rules at the time. There is no date on the poster, but I'm guessing 1964-1965. They're showing a price of $11.97 for the 1610D; it was $20 in 1970. Unfolded, the poster measures 21"" by 16 ¼"". Each of the 4 pictures is half of one side of the poster."