Assimilation Tubule

Assimilation tubules were a pair of flexible needle-like devices that extended from the wrists or fingers of Borg drones. These tubules initiated the assimilation process by injecting Borg nanoprobes into a victim's bloodstream, and were capable of penetrating any armor or energy shielding known to the Federation. Assimilation tubules also allowed drones to interface with technology. (Star Trek: First Contact; VOY: "Scorpion")

In their first appearance and in "Scorpion", the assimilation tubules appeared to be rigid, talon-like weapons; however, in later appearances on Voyager, the tubules seemed to be flexible objects, more along the lines of "tubules". This may indicate that they could stiffen depending on function. Given that the technology is not seen in any Borg appearance prior to Star Trek: First Contact, it is possible that the Borg assimilated the technology sometime after their last appearance on TNG.