Dead reckoning computer (E6B) wellworn. Has been used to navigate B-52, C-47,C-54, T-29, A/B -26 toAlaska,Adak Is.,Midway Is.,Wake Is.,Guam,Mactan Pi., Manila Pi.Vietnam, Greenland, Iceland, most of Europe, North Polar regions. Includes a copy of AF 21b form for computing celestial 3 star fix by H.O. 249 tables. How it was before GPS!