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
Circular slide rule with plotting scale and course protractor for aeronautical use, E6B-1A flight path computer by Jeppesen & Co., Denver, Colorado, aluminium in plastic case, plus plastic aide-memoire Air-Aid rule copyright 1971 by AOPA
Circular slide rule with plotting scale and course protractor for aeronautical use, E6B-1A flight path computer by Jeppesen & Co., Denver, Colorado, aluminium in plastic case, plus plastic aide-memoire Air-Aid rule copyright 1971 by AOPA