Just the thing for the well-equipped naive test shot participant, styled to accent any death-town decor. These calculators purported to permit you to estimate the radiation dose and yield from an observed nuclear burst. They're a lovely little testament to the kind of self-delusion rampant during the cold war. Did the military honestly believe that one's first reaction to the blinding flash would be to rummage around for one's circular slide rule, then count seconds for the fireball illumination time? And even given that belief, did they assume the cheap plastic would survive the heat? Some people, i tell you.