Yes, this is the famous slide rule!!! I started engineering school in Russia and that's what we used! Then I finished my education in the U.S and they switched to calculators in the U.S by then. I was told by older students in my US college that pocket protector with a bunch of pens and slide rule attached to the belt on the waist is a sure sign of a geek:-) By the time I arrived in the U.S, slide rules disappeared but pocket protectors still ruled:-)