An essence cuff on Sayeon Lee's wrist
An essence cuff is a device that is generally worn on the wrist that saps the Essence of the one wearing it, making it almost impossible to activate one's gift. The cuffs are often used by the Corps to restrict the usage of Aberrants gifts and essence. Depending on the level of danger the Aberrant presents determines what setting the cuff is placed on.
The cuff have three settings, the number of red lights represent the setting the cuff is on. One red light represents the lowest setting while three red lights represent the maximum. The lowest setting causes lightheadedness and nausea, while the max setting, as described by Ryujin, left her unable move and unable to active her gift for days. The effects of leaving the cuff on the maximum setting for a long period of time also includes making the victim feeling like an ordinary person to other Aberrants.