Abstract: The disclosed system, device and method for providing a substantially leak-proof tube/manifold seal generally includes a partially deformable polymeric ferrule (100), a retaining ring (110) and a nut (130) configured to drive and deform the ferrule (100) against a receiving manifold surface (144). Disclosed features and specifications may be variously controlled, adapted or otherwise optionally modified to improve tube seal seating and/or engagement. Exemplary embodiments of the present invention generally allow for the use of tube coupling hardware (e.g., ferrules) that would otherwise need to be reworked, replaced or discarded.