Pair of two hinges & pin or pivot whose axis are perpendicular to each other are connected to a floating gimbaled-ring.
Advantage of absorbing pressure thrust, supporting the dead weight of the system, transmitting loads through the gimbaled structure, preventing torsion & reduce forces on system.
Applied to complex piping system were proper anchoring & guiding may not be feasible.
These joints are capable of absorbing angular motion in all planes.