The phrase "in ducts" is typically used to refer to something that is situated or located inside a narrow tube or channel. Antonyms for this term could include "out of ducts", "above ducts", "below ducts", "around ducts", "away from ducts", "beside ducts", or "outside ducts". These phrases would suggest that the subject in question is not confined to or limited by the narrow space of the ducts, but rather exists in a different location or in a more open space. This can help to provide context and clarity when discussing the location and movement of various objects or materials.