Nice piece of Pilot navigator equipment from the 1960’s. The Air Navigation Dead reckoning type CPU 26A/P comes with sleeve and with manual. Mostly made of metal in the USA with Mil (Military) numbers and contract reference as well. Some signs of use and age but in overall good condition. It measures ca. 19 cm or 7 1/2 inches high. Check the attached video on how to work your vintage man tool : slide rule operation instructions!