Abstract: An effective seal is provided which fulfills the requirement for a trouble free joint, particularly "V" band joints which are dependent on accurately controlled tube end flanges. Rolled sheet metal flanges are particularly subject to excessive leakages due to deformation during handling and installation. The normal tendency to stop leakage on any joint is by additional torque of the coupling. With the rolled sheet metal flanges, this causes additional deflection of the flange and aggravates the leakage problem rather than reducing it. Furthermore on aircraft environment systems leaks are extremely difficult to pinpoint and time consuming to repair.