The MSIG – 1 Multi-sigma slide rule was produced by the US Defense Nuclear Agency to assist military planners in calculating the probability of damage resulting from a nuclear detonation.
The rule is 8″ [205 mm] in diameter and produced by Perrygraf. It was designed by the DNA and is dated April 1987. This rule is very collectable but the hardest to find of all the DNA slide rules. The one shown was never issued and is in mint condition.
The MSIG -1 was the last slide rule to be produced by the DNA. After that they only supplied software for use on desktop and hand held machines. A list of the slide rule and software can be found in this post.
The complete package as issued consisted of a binder, hard cover, documentation, slide rule and two floppy disks.