Unless it is specified that a Self may be used by several people, every Selfic structure is to be used by one person only, as it resonates with his or her specific energy frequency. It would therefore not be effective on others.
The Self usually synchronizes with the wearer in a half hour, by simply wearing it in the appropriate way. In some cases, however, the Self needs to be programmed by a Selet person, using the user's name and date of birth. When this is the case, it is specified under the self's description.
Because every Self adapts to the energy field of its user, it often happens that Selfs that are worn with regularity change their shape in time. This is a sign that they are functioning perfectly. It is a "trace" of the personal energy field of the wearer.