A duotronic enhancer was a component of 23rd century starships.
In 2369, Montgomery Scott asked Geordi La Forge what happened to the duotronic enhancers he expected to see on the USS Enterprise-D. La Forge explained that they had been replaced by the more efficient isolinear chips about forty years ago. (TNG: "Relics")
As evidenced by the first draft script of "Relics", this term was originally "biofilter TECH", where the latter word was to later be replaced. This was changed to "duotronic enhancers" by the time the final draft of the script was issued. [1]