Isolinear rod

An isolinear rod was a type of information storage technology used by the Cardassian Union.

Holosuite programs could be stored on isolinear rods. 

Quark used isolinear rods to gain access to the various Cardassian systems on Deep Space 9. 

On her birthday in 2376, a Changeling who visited Deep Space 9 gave Kira Nerys an isolinear rod that held a message from Odo. (SS DS9 (Urgent Matter))