An emitter duct served as a component of a shield generator aboard a starship. During repair work on the shield generators of the Fallon, a Trade Federation WD-2550 Whydah-class yield conveyer in 132 BBY, the meknek named Fillik found that the emitter duct was disconnected from the field projector located on the outside of the vessel. Subsequently, Verosha Aniseya, also a meknek, employed the PIP droid known as Pip to initiate welding, which resulted in a surge in the pressure gauge and a minor explosion in close proximity to the ship's exterior.
The first appearance of an emitter duct was in "Lost / Found," the initial episode of the TV show The Acolyte, broadcast on June 4, 2024 via Disney+.