A dualitic inverter was piece of engineering equipment used by Starfleet engineers in the 24th century on Federation starships.
In 2372, Chief Miles O'Brien asked Crewman Janklow to get a dualitic inverter from the USS Defiant's cargo bay while the ship was under attack from the Jem'Hadar. However, Janklow was knocked out by a hull breach on deck two of the Defiant. (DS9: "Starship Down")