Design and Function EditGenerally, the monitor device was left in for about three years. The longer a monitor was used for, the more dangerous it was to the subject when removed.
The monitor was placed in the back of the neck, and screened nervous impulses in the spinal column, which could be studied to determine a person's true personality. Monitors also allowed the International Fleet to survey the activity of the person with the monitor and others around them, in order to judge wether a person was fit for Battle School. The International Fleet used the monitors to watch promising children and decide whether they had the right traits for Battle School.