By Keuffel & Esser Co., New York, early 20th century, slide rule cylinder in fitted mahogany dovetailed case, No. 4012 and serial #2035 on both instrument and case. With original instruction manual dated 1920.

Case 6.5 x 24 x 6.5 in.

Scuffs to the case from normal use as expected; light brown spotting on the bars.

$500 - 900