A suppressing collar is a collar used to make a spellworker become unable to work magic. It is binding to the prisoner it’s on if they have been convinced that it will actually bind them – and it will have other freedom-limiting powers if the prisoner’s subconscious can be convinced that it has such powers. They are made as collars as everyone knows that collars are used to limit freedom, so it already has that subconscious effect. Oftentimes the prisoner will have already seen similar artifacts at work limiting the powers of people who have been caught previously, and thus the subconscious draws conclusions of the power of these artifacts. Further, when a person is first subjected to it they are usually ‘trained’, by a person giving them a chance to try to take it off or escape with it, whereupon the subconscious takes that to imply that the artifact is going to prevent them from escaping or taking it off – and thus the artifact has that effect on the person.