An early version of the Log Log Duplex Decitrig rule, this one's pretty similar to that rule, but lacks the LL02 and LL03 scales, is thicker and heavier, and has the glass frameless cursor that lots of earlier K&E rules had. This one also has the previous owner's name, "J. W. Sawyer" engraved right on the rule. I'm guessing if you paid K&E; some ridiculous amount of money, they'd do that for you. I also have a 20" version of this rule that's just too big to fit on the scanner. Goshes, it's big. It's virtually identical to this one modulo the engraved owner's name and that the 20" one has a nicer case: a gigantic orange monstrosity. This is the slide rule i bought my dad for christmas. I'd been holding off buying one for myself, mostly because i already had the later model. However, this one was a gift from kendra's mom, who, when she heard i was collecting slide rules, apparently put an ad in the paper and now has the entire retired-engineer population of her hometown calling at all hours of the day and night offering slide rules. Everyone should have parents that cool, i tell you. Anyway, i'm glad i kept this one; i'm actually really quite fond of the older K&E's. They tended to be heavier and feel more substantial than the later models. Here's a fun question: i've heard claims that some K&E's were mahogany, and that some were laminated with ivory. Which ones? When did they start using celluloid, and when did they then switch to their "ivorite" plastic? And were all their rules mahogany? i don't think so, but i'm only guessing; the earlier rules, like this one, appear to be made of a heavier, darker wood than the later models. Someday, i really need to buy some back issues of the Journal of the Oughtred Society.