SF-3

It's a ruggedised and less efficient Minuteman II with the third stage removed, basically.

Mod 0: Original missile, carries up to three 170 kiloton bombs. All silo based. 80 fielded, currently carry only one warhead.

Mod 1: Introduced in 2004, carries an earth-penetrating Maneuverable Re-entry Vehicle with a 350 kiloton warhead. 20 fielded in mobile launchers.