Reinforced ring expansion joint with equalising ring and reinforcing ring bellows are usually chosen for high pressure installations. Equalising rings are solid stainless steel rings fitted externally on the bellows of the reinforced ring expansion Joint. The rins are precisely machined so they fit into the root between each of the bellows convolutions. The purpose of the rings is to reinforce the bellows against internal pressure. By adding moment of inertia thto bellows cross section, this counteracts the bellows ability to blow out or buckle (also called squirm) and enhances its stability and pressure integrity. Bellows with reinforced rings can be made for any type of expansion joint(axial, lateral or angular etc.) The disadvantage of the reinforced ring expansion joint having reinforced bellows are the significantly increased stiffnes of the bellows and their limited movement properties.