A bracelet was a decorative piece of jewelry usually worn around the wrist.
The Sirah used a bracelet with a fragment of an orb in its center to control the Dal'Rok. (DS9: "The Storyteller")
Miles O'Brien gave his wife Keiko a gold bracelet while they visited McKinley Park. (TNG: "Power Play")
Young Bajoran girls often received a Bajoran betrothal bracelet to indicate they were "promised" to another for the purposes of marriage at a later date in their adulthood. (DS9: "Fascination")
Some individuals or groups who seeked to enslave or coerce others used a control bracelet for the purposes of torture and discipline. (TOS: "Spock's Brain")