A distribution node.
A distribution node is a device on Borg vessels that controls the distribution of data to various areas of the vessel. They resemble small green pyramids.
In late 2366, an away team from the USS Enterprise-D boarded a Borg cube headed for Earth and destroyed several distribution nodes, in order to attract the cube's attention and give them a chance to use their main deflector weapon. (TNG: "The Best of Both Worlds")
In 2373, while aboard the wreckage of a Borg cube destroyed by Species 8472, Chakotay ordered Harry Kim to access a distribution node and attempt to download the tactical database. (VOY: "Scorpion")
In the game Star Trek: Voyager - Elite Force, destroying distribution nodes on Borg vessels deactivated nearby forcefields and nearby drones.