RAND Corp. Bomb Damage Effect Computer (ca.1960)
The great thing about the RAND Bomb Damage Effect Computer is that it is made of aluminum rather than plastic or (heaven forbid) cardboard—this is a high quality item. Not surprising when you consider that it was produced for the military.
The copyright date is 1958.
It allowed the aircrew of a bomber to predict the size of the crater produced by the thermonuclear weapon they were about to release. It also gave the pilot some idea as to the size of the fireball and the altitude that was required to minimize the contamination of the aircraft by fallout. In other words, it did much the same thing as several other slide rules. e.g., the BLR Nuclear Weapon Effects Computer.
The fact that it has the word "unclassified" on it suggest that there was a classified version. Perhaps, this particular example was intended for training rather than actual use.
One imaginative reference to this device (Greeley 2011) indicated that it was used by RAND employees "to estimate megadeaths." A nice example of dramatic license.
Size: 4" diameter
Greeley, B. "Paul Baran, The Anti-Strangelove". Bloomberg Businessweek. March 31, 2011.