After spending twenty subjective years in an Argrathi prison, Miles O'Brien worked with Jake Sisko in retraining his engineering skills, so as to not embarrass himself in front of the repair crews, by reviewing various engineering tools in the cargo bay. Among the tools he recognized were the interphasic coil spanner, the ODN recoupler, and with a bit more difficulty, the quantum flux regulator, Mark III. (DS9: "Hard Time")