Isolinear rod

Isolinear rods are long, thin and cylindrical in shape, having a translucent dark amber tint. These small rods interface with information storage and processing devices which are employed by the Cardassian Union aboard their starships and other facilities. They are also used aboard the Bajoran, formerly Cardassian, facility of Deep Space 9. The rods are similar in principle to the Starfleet-issued isolinear chips used aboard Federation starships. (Star Trek: Deep Space Nine)

In 2369 Quark used two isolinear rods to pass the security clearance five to get access to a station layout of Deep Space 9's command level. 

The same year the senior staff of Deep Space 9 tried to download all the data from "Pup" onto six isolinear rods. 

In late 2369/early 2370, a freighter operated by Subytts was involved in smuggling defective isolinear rods to Bajor. 

Isolinear rods are color-coded with labels that correspond with what particular information they pertain to. For instance, white-labeled rods contain data relating to engineering system controls while red-labeled contain library and information storage. 

In times of heightened security aboard Cardassian ships, isolinear rod banks could be protected by an anti-personnel force field.