1931. 8 1/4 inches in diameter, aluminum and plastic construction. Three plastic cursors present and with some yellowing. Metal washers on both sides present, one with a hairline crack. The finish on the rule is quite nice and what minor soiling there is would clean up nicely. No case or instructions. Copyrighted 1931, with a note on the other side indicating it was patented 1-17-1922.
These were made in a variety of sizes and forms - this is the largest we've seen and has a nice presence. Very Good.