An adjustable collar stay has two components: a) a housing, and b) a movable piece having a wider head and elongated portion, the elongated portion adapted for slidably moving within the housing. The wider head is at least one cross-section disposed perpendicular to the point of entry (portal) into the housing, preventing its entry thereto. A spring-loaded pin, situated within the housing, engages with a pit, cut into the side of the elongated region of the movable piece. By grasping the head and pushing it transverse to the direction of the housing, one dislodges the pin from a pit, and moves the movable piece with respect to the housing, in order to elongate or shorten the entire device.