A decoupler includes a short bellows of ten or fewer convolutions, an internal liner spaced from the bellows internally and a cover spaced radially outward from the bellows providing an air gap both internally and externally of the bellows. The liner has a free-standing downstream end proximate a damper which is captured by a cover, inner damper ring and slide ring. Two decouplers are mounted in series to accommodate angular, axial and lateral displacement when operably connecting two end pipes and one central pipe.