The Otis King was marketed as a slide rule for everyone including anyone constantly working with mathematical problems. It was considered simple, quick, accurate and durable. This compact calculator measures 6 3/4” in length; fully extended 10” in length.  

This Model K, Type B, Otis King consists of a chromium plated holder, a metal cylinder that slides into the holder and a black metal tube that fits around the cylinder and can move up and down the scales. The scales are marked 414 and 423. The end of the metal cylinder is marked “Made in England” together with the number V2143. At the top of the cylinder is printed Patent No. 183723 which is a United Kingdom patent in 1921. Included with the calculator is the original cardboard box with a label “Otis King Calculator Model K No. W923”.  There are also 8 pages titled “Outline Drawings of Calculator, showing correct setting of arrows to scales” by Carbic Limited, London, with operation instructions and calculation examples. (Carbic Limited was granted manufacturing the Otis King patent.) Although the pages are separated and worn, they can still be read.  The calculator appears to be in good working condition.

This calculator was a mathematical genius in its day and is a wonderful item to be included in your collection of scientific inventions that improved everyday life in the 20th Century. Please review the photos for pictorial description. NO RESERVE!