w66

The W66 thermonuclear warhead was used on the Sprint anti-ballistic missile system, designed to be a short-range interceptor to shoot down incoming ICBM warheads.
The W66 was a low-yield (details not declassified, but reportedly a few kilotons) warhead designed to destroy or disable an incoming warhead using neutron flux and, to a lesser extent, X-ray and blast effects.
The W66 was 18 inches in maximal diameter and 35 inches long, with a weight of approximately 150 pounds.

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