An iso-modulator was a type of tool used aboard starships.
Seven of Nine had an iso-modulator that she had enhanced to correct hull ablation. In 2376, she took this tool with her on a mission to explore a collapsing micro-nebula near Norcadia Prime, in case their shuttlecraft encountered a meteoroid stream. Tom Paris compared her preference for that specific iso-modulator to B'Elanna Torres' Toby the targ. (VOY: "Tsunkatse")