The device attaches to the applicant’s nerves. When used in Lunars, it prevents them from manipulating bioelectricity and from seeing hallucinations associated with “Lunar Sickness”. When used in an Earthen, it prevents them from being manipulated by Lunars.
In Cinder, it is mentioned that Cinder has a device that prevented her from using her lunar gift, although little other information regarding the device is mentioned.
In the book Scarlet, it is revealed that Michelle Benoit also has the device, and is able to resist manipulations from the Lunar Special Operatives who kidnapped her in order to get information from her regarding Selene’s whereabouts.
The device also comes up in Winter during the trial of Linh Adri on Luna, presented as evidence against her. Levana asks Adri why she did not choose to capitalize on the device once Garan passed away. Adri says that she had no knowledge of the device. Levana said that Adri was lying, although this was untrue. It is also mentioned that the patent and all other documents regarding the device had been destroyed shortly before the trial. Adri eventually made it back to earth.
The device is later significant regarding the alliance between Earth and Luna. During the meeting, the Australian Governer-General Williams brought up the issues with free travel between Earth and Luna — the possibility of Lunars using their gift to manipulate Earthens. Cinder mentions the device and reveals that although the original paperwork was destroyed, there is a blueprint stored in the android Iko. Linh Adri later negotiated a royalty for the device, bringing her great wealth.