Atlas II was an American expendable launch system, used between 1991 to 2004, developed by Lockheed Martin to launch a variety of different satellites. The vehicle operated out of Space Launch Complex 36A and 36B at Cape Canaveral Air Force Station and Space Launch Complex 3 at Vandenberg Air Force Base.

I recommend turning on "Advanced tweakables" in KSP settings.

To download each variant of Atlas II, go to the "Files" section.

Also Don’t forget to download the flags for Atlas II in the "Files" section.

Here are my other projects.

Atlas II, Atlas IIA, Atlas IIAS

Modified Atlas G

Centaur D1A