- For other uses, see Type 4.
Type 4 was a material option, an Alpha Quadrant Alliance designation for the visual appearance of a spacecraft's outer hull, i.e. a vessel's "skin". This version of Type 4 was available for Federation Starfleet starships and shuttlecraft. It was one of the default materials for ships of the line in 2409. (STO - Klingon War mission: "Welcome to Earth Spacedock")