RARE 12" FOLDING METAL RULER-STREET CAR HEATERS-1920/30S-CHICAGO

A vintage advertising specialty item from 1920-1930's & in VERY GOOD CONDITION. This is a folding metal 12" ruler. It folds in 3 sections & fits into original leather case. Case has a tear at the end. Appx. 4.25" long when folded. Advertising from: CALORIFIC VENTILATING HEATING COMPANY, CHICAGO. M'F'RS STREET CAR HEATERS. A very rare treasure & a great addition to that special collection!