Abstract: This clamping collar, notably for the automotive industry and more particularly for coupling and sealing the joints between the component elements of an exhaust and muffler system, permits the end to end coupling of these elements. The collar consists of a flexible strap bent to an open-loop configuration and adapted to encircle the pipe end, the ends of the collar being interconnected by tightening means such as bolts. The collar ends are stiffened in the longitudinal direction by using longitudinal plates disposed inside the bent ends of the collar; the tightening means extend through holes formed in the collar ends and in plates. The plates provide a better distribution of the tightening stress. The collar is also provided with leakage-preventing means in the form of flexible tongues possibly lined with thin metal blades which become operative when tightening the collar in position.