The Collector cruiser has a heat signature similar to the cruisers of other Mass Effect races, as the scan operator of the SSV Normandy quickly classed it as a cruiser, despite its unfamiliar configuration. It's actual volume and mass are much greater, comparable to a dreadnought. Despite its large size, it is capable of landing on a planet's surface.
The Collector cruiser's hull appears to have been built from an asteroid, as large portions of it appear to be natural rock. The basic shape of the ship is a tube, with engines on one end and an enormous weapon port on the other. Much of the ship's interior is a hollow cavern lined with the pods that the Collectors use for transporting captured colonists. Floating platforms allow rapid transport within this space.
The ship is armed a massive forward proton beam and several smaller side beams. The forward weapon was powerful enough to cripple the SSV Normandy with just a couple of hits. For defense the cruiser uses kinetic barriers of unknown strength. Overall, the ship seems to be designed more as a transport than a warship, despite its powerful weaponry.
The sensor systems of the Collector cruiser are advanced enough to overcome the experimental stealth technology developed by the Systems Alliance.