The Pomson 6000 is a 4-shot replacement for the Engineer's default shotgun. While it fires less shots before reloading, this is made up for by the fact that it does not run out of ammunition, it's shots cannot be deflected, and said shots continue through enemy players to damage anyone caught in the gun's line of fire. These are all attributes shared with other Dr. Grordbort's weapons.
The Pomson 6000 also has some unique features. Enemy Medics hit by an energy bolt fired from the gun lose 10% of their ubercharge meter per hit and enemy Spies lose 20% of their cloak meter.
This weapon is part of the Dr. Grordbort's Brainiac Pack set for the Engineer. However, there is no set bonus for wearing all of the pieces of the set at the same time.