A multi-purpose adjustable quick expandable installment which can be quickly and finely adjusted and ascend or descend freely, by a snap design which adjusts ascending or descending with a slope principle, based on a mechanical principle that a force is constant if acting on a same area and an opposite force compensates with the force. Through a structure which follows the law of action and reaction to compensate with a sliding force which occurs naturally, a stable movement without moving accidentally is formed.