Signedon top of rule: THE C-THRU RULER CO. / BLOOMFIELD, CONN. U.S.A. THE C-THRU RULER CO. / BLOOMFIELD, CONN. U.S.A.
Inscribedon top of box: green mark
on side of box: 3088 CLEAR / 3088 CLEAR / 15 CLEAR
FunctionParallel rules allow for the drafting of precise parallel lines.
ProvenanceLionel Spiro, Brookline, MA; Gift to CHSI, 2014.