Gimbal Expansion Joints usually have a singular Bellows component.  Gimbal expansion joints are designed to permit  the angular rotation in any direction by using two pairs of hinges that are connected to a common floating Gimbal ring.  The Gimbal ring, hinges, and pins are designed to restrain the thrust of the Expansion Joints as a result of pressure and external forces.  The advantage of Gimbal Expansion Joints is that they are not limited to only single plane systems, making them very useful for various applications.