At this Readiness level, personell on leave are recalled,SAC or Strategic Air Command would, in bygone days, have B52s on the tarmac, fuelled, and be ready to fly at short notice.

These would be eqqiupped with ICBMs (Inter Continental Ballistic Missiles) and or SRAMs (Short Range Attack Missiles) which would both contain Nuclear Weapons, or possibly other Weapons Of Mass Destruction.