Cardboard case is gold-stamped. One end of case has been repaired with black tape. Rule with single slider. One slide-rule face and slider there are measurements pertaining to radius, the reverse side which can be read through a transparent plastic cursor (patent 2,086,502) which moves along grooves on the sides of instrument has trigonometric scales for sines, equal parts, and tangents.
Inscription/Sig.
"KEUFFEL & ESSER CO. N.Y. / PAT. JUNE 5, 1900 / MADE IN U.S.A. / <405 3- 5>"; Case is gold-stamped "KEUFFEL & ESSER Co./POLYPHASE/REG. U.S. PAT. OFF./SLIDE RULE."
