One which doesn't exist. The 'tech' ranks were replaced by the Specialist ranks (of which, only Specialist 4 is still in use).
Sergeant Major of the Army is the highest rank NCO.
Anyone in the US Army can lose their rank - in the late 1990s, the Sergeant Major of the Army was demoted. It's not as easy for an SFC to lose their rank as, say, a Specialist or Sergeant, but it can happen.
In the US Army, General.
The highest Non-Commissioned Officer rank in the US Army is Sergeant Major of the Army. The current SMOA is Kenneth O. Preston.
In the US Army, there's two ranks - Specialist, and Corporal. In the US Marines, it's just Corporal. The Specialist rank in the Army is not an NCO rank, whereas Corporal is.
Lieutenant Colonel.
captain
Usually, a Captain.
General of the Army.
In the US Army, a full bird refers to a Colonel, which is the rank between Lieutenant Colonel and Brigadier General.
General of the Army (five stars). However, this is a special rank used only in wartime. Currently, General (four stars) is the highest achievable rank.
His rank is Captain, his pay grade is 0-3.