The device is inspired by a Longleg's sonic blast ability. The weapon consists of a modified Longleg head and concussion sac. When active, the device emits sound waves that render the victim defenseless. To prevent himself from being affected, Dervahl used specialized earpieces to block out the sound waves.
The sonic device was created by Dervahl, made from modified Longleg components.
As the first stage in his plot to destroy Meridian, Dervahl called Ersa to Dimmed Bones, offering to parlay. Sensing it was a trap, Ersa brought a group of Vanguard along with her. However, Ersa and all of her men fell victim to the sonic device, allowing Dervahl and his forces to defeat them with ease. Ersa was captured and brought to Dervahl's Camp, where she was kept restrained with a sonic device.
After breaking into the Palace of the Sun, Dervahl activated one of these devices to bring everyone inside to their knees. However, when the bomb he built didn't go off as intended (thanks to the efforts of Erend and Aloy), Dervahl and his men left to investigate. With their attention elsewhere, Aloy followed Dervahl through his own secret pathway and destroyed the device.