The USS Audacious Aggressor class vessel was built
in a secret section called the Bahleyhem shipyards.
There were Eight Aggressor class vessels.
The NX Aggressor
The USS Oriskany
The USS Nemesis
The USS Avenger
The USS Extol
The USS Audacious
The USS Aries
The USS Olorun
Well in the USS Audacious world, Section 31 was
FINALLY able to get the cloaking device to work with an experimental ship
called the NX Aggressor.
That ship was later destroyed in battle and the Audacious is the only
surviving
ship with the successful Interphasic cloak..
The Interphasic cloak is an ENORMOUS power drain. And when the cloak is used it
drains systems so extreme that if cloaked for more than five minutes.
The cloak will drain most systems.
Only life support and thrusters remain..
So you can't go willy nilly with the ship and take on an entire fleet
single handedly..
The cloak is a cleaver and highly illegal device that Starfleet denies
any recollection of..
(Off The Record) of course..
The liaison between Star fleet and the infamous Section 31. Admiral
Seals, is through a Starfleet Admiral named Nachayev.