The A'dam is most commonly formed out of a flexible silver collar and bracelet, joined by a long silvery leash. The one wearing the bracelet (called the "Sul'dam" in Seanchan) is in control of the A'dam, and has the woman wearing the collar (called a "damane") completely at her mercy.
"Setalle took the a'dam from Mat and fumbled at the flat segmented bracelet on one end of the round silver leash. The whole thing was made in segments, fitted together so cunningly you could not see how it had been done."
Experimentation by Elayne revealed that the cord is not strictly necessary, as she was able to fashion an A'dam that did not require one. However, the cordless version comes with the notable downside of allowing the one wearing the collar a greater degree of physical freedom.
The first a'dam was made by Deain Sedai, a Seanchan woman who wanted to assist Luthair Paendrag Mondwin in his consolidation of the continent by giving him an instrument to control female channellers who opposed him. She was later collared herself by an a'dam, and it is said that her screams "shook the Towers of Midnight". While the exact timing of this event is unclear, it must have occurred in Luthair's lifetime, so sometime in the latter days of the Free Years calendar.
The one wearing the bracelet must have the capacity to learn how to channel, though she is not required to have any active control over (or even knowledge of) the One Power.
In order to be able to be controlled by the collar, a woman must either possess the Spark, or have trained enough to gain a minimum level of proficiency and familiarity with the One Power. Ironically, Sul'dam gradually learn the basics of channelling through their control over Damane, and thus eventually become susceptible to the control of the collar themselves; however, this fact is not generally known within the Seanchan Empire.
The a'dam protects the damane, preventing her from burning herself out. This may have been incorporated into the original design to prevent any possibility of a captive deliberately burning herself out. This also enables the Sul'dam to Force the damane, allowing them to quickly reach their full potential.
Effect on society and life
Wearing the a'dam marks and defines the social status of female channellers in the Seanchan Empire; the leashed woman is called a damane (Leashed one), and the woman who holds the bracelet is a sul'dam (Leash holder).
At the time of its invention, the fact that Sul'dam could learn to channel was common knowledge, but this knowledge was either deliberately erased or slowly forgotten over time. The Seanchan believe that only those women who are born with the spark can channel. Ironically, while damane are viewed as dangerous, subhuman property to be controlled, sul'dam are valued and well-regarded members of society due to their skill in working with the women who actually wield the One Power.
The rediscovery of the Sul'dam's ability to channel by certain members of Seanchan society (including some sul'dam) at the end of the Third Age has the potential to rock their society to the core. However, as of the beginning of the Fourth Age, this information has not yet been widely disseminated.
Differences between willingly formed Links and the a'dam
The a'dam creates a circle of two female channellers led by the wearer of the bracelet. The lead cannot be passed over to the wearer of the collar, the woman who wears the bracelet must always leading the circle.
A sul'dam is able to feel her damane's emotions and physical reactions, and is able to influence or change them through the a'dam. Were she to channel herself, she would be able to combine her own abilities with those of the other woman to channel a single, combined set of flows herself.
Gender mixed use
While a normally formed circle of one man and one woman is possible, wearing the bracelet of an a'dam causes intense pain to a male channeller and often kills him. This is likely a consequence of the fact that in a circle of one man and one woman, a woman must always initiate the bond, but the a'dam attempts to force the creation of a link controlled by the wearer of the bracelet, which would be the man in this case.
A woman wearing the bracelet might be able to control a man wearing the collar, although it is generally believed this would be difficult to do due to the higher inherent strength of male channelers. (The Forsaken attempted to capture Rand al'Thor using a similar Ter'angreal with two bracelets, allowing two women to control one man, thus overcoming this issue.)
A male channeler touching an a'dam causes intense pain both to the women wearing the bracelet and the collar as well as the man. This makes it nearly impossible for a man to physically open the A'dam. 
"He [Rand] put a hand to the collar of the nearest, and felt a jolt that nearly numbed his arm; for an instant the Void shifted, and saidin raged through him like the snowstorm a thousandfold. The damane's short yellow hair flailed as she convulsed at his touch, screaming, and the sul'dam connected to her gasped, face going white. Both would have fallen if not held by bonds of Air."
Females and any males who cannot channel can open both the bracelet and the collar, or remove the collar from a damane when she is not linked with a sul'dam.
"The catches were a simple matter for him [Mat] the bracelet easiest. That was just a matter of squeezing the right spots, top and bottom, not quite opposite the leash. It could be done with one hand, and the bracelet popped open on one side with a metallic click. The collar was a little trickier, and required both hands. Putting his fingers on the proper spots on either side of where the leash attached, he pressed, then twisted and pulled while holding the pressure. Nothing happened, that he could see, until he twisted the two sides the other way. Then they came apart right beside the leash, with a sharper click than the bracelet. Simple. Of course, figuring it out had taken him nearly an hour, back in the Palace, even with what Juilin had seen to help."
In a normally created link there is no feedback regarding the feelings or emotions of the participants in the link.
Burned out channellers
The a'dam includes a number of useful characteristics for maintaining the captivity of the damane: It incapacitates the damane if she makes any attempt to open the clasp on the collar, or move an empty bracelet from where it has been placed by a sul'dam.
- It allows the addition of emotional sensations to the damane's worldview; she can thus be punished immediately and unavoidably for any transgressions, a fact used liberally in most training.
- Any pain inflicted on a sul'dam is also felt by the damane twice as severely, effectively preventing a damane from attacking her sul'dam.
- A damane cannot pick up a weapon. If a damane thinks of using an object as a weapon, she will not be able to pick it up until she completely expunges the thought from her mind.
- When the bracelet is not worn by a sul'dam, moving it will incapacitate the damane with pain and nausea. This prevents her from escaping even when unattended.
- A sul'dam can make a damane embrace or release the True Source at will.
- Damane are unable to form circles as other channelers can, because they are already linked with their sul'dam. This fact constitutes an extraordinary weakness with regard to using damane against other channelers.
Elayne Trakand created a unique a'dam in order to hold Moghedien captive. This example had a few special features allowing it to be kept secret more easily. Most importantly, the bracelet and collar were not joined by a leash. Because of this, Moghedien could move around more freely, as doing so did not require her to move the bracelet.
- Main article: Domination Band
A similar ter'angreal exists to allow control of male channelers. It consists of a collar and two bracelets, in separate pieces, all made of black cuendillar. Though it has been referred to as an "a'dam for men," it should be noted that it dates from the Breaking Of The World, centuries before the a'dam was invented. This version of the device allows for far more control over the subject, but it requires two women to maintain that control as opposed to one. If only a single woman attempts to use it, a high degree of possibility exists that the device will, given time, give the subject complete control over whomever is wearing the bracelet.
Originally only one such set was known. This fell into the possession of the Seanchan, who made at least six copies.