The name comes from the word "hooah," which is commonly used by American military personnel (Marines tend to prefer the word "Oorah!"). "Hooah!" is a battle cry which, according to the official website, has come to mean "anything and everything except no." The bar originally had HOOAH! and the US Army coat-of arms on one side and OOO-RAH! and the Marine Corps coat-of-arms on the other; the new wrappers have both logos on the same side.
The military HooAH! Bar comes in apple-cinnamon, chocolate, cran-raspberry, peanut butter and raspberry flavors. The smaller First Strike bars (provided in the concentrated First Strike Ration) come in Apple-Cinnamon, Cran-Raspberry, Chocolate, Raspberry and Mocha flavors. The civilian HOOAH! bar only comes in Chocolate Crisp, Peanut Butter, and Apple-Cinnamon flavors. It is also available as a energy drink, subtitled "soldier fuel."