The Tallneck Array is a special item in Horizon Zero Dawn: The Frozen Wilds that can be obtained from a Scrapper during the side quest Tallneck: Frostfigures.
History
Horizon Zero Dawn: The Frozen Wilds
When machines began scrapping the fallen Tallneck in the Frostfigures, its Tallneck Array was taken by a Scrapper. In order to reactivate the Tallneck, Aloy retrieved the Tallneck Array from the Scrapper and returned it to the Tallneck, installing it among its tails. That, along with returning the Tallneck Actuator and Stabilizer, allowed her to reactivate the long dormant machine.[1]