Twin colour pencil
A double ended pencil divided approximately equally into two halves of blue and red wax based coloured leads. First introduced in 1909 for use by the German post office, these quickly gained favour as useful tools for book-keeping, note taking, marking, correcting text, and if the film Downfall is accurate, military planning. At 9mm these are thicker than standard pencils, for greater comfort with rapid work. Made by the Koh-I-Noor Hardtmuth company in České Budějovice, Czech Republic.