When necessary, these ships could mask their warp signatures to prevent detection (DIS: "Saints of Imperfection", "Perpetual Infinity"), and could also emit graviton beams from their deflector arrays. (DIS: "The Red Angel")
Ships of this type were smaller than contemporary Crossfield-class vessels and were constructed with a darker hull color than other Federation vessels of the era. The primary hull was triangular, similar to the 22nd century Warp Delta design used by United Earth.
These vessels were able to retract their nacelle pylons when not at warp.
Internally, the NCIA-93 type featured a two-storey bridge and a drab, overall minimalist design. Corridors and rooms aboard these ships were considerably darker. (DIS: "Point of Light", "Light and Shadows", "Saints of Imperfection")
Eaglemoss/Hero Collector's Star Trek: Discovery The Official Starships Collection partwork identifies this type of vessel as a Section 31 "Stealth Ship".