Phase II Study I
Nothing is known about this starship-class whose construction seems to date back to the late 23rd century or earlier.

This is the first of two study models designed by Ralph McQuarrie for the cenceled TV series "Star Trek Phase II".  The nodel briefly appeared on screen in TNG: "Unification" and was probably visible in TNG: "Best of Both Worlds" too.  The ship class is named "Phase II study" in the list due to the lack of a proper name.