Abstract: A plastic clamping ring for securing and sealing the joint between adjoining peripherally flanged ducts has a generally V-shaped cross-section provided with a molded in place or bonded seal which engages the flange rims. A latching feature permits the ends of the clamp to be temporarily latched in position to frictionally limit, without preventing, adjustment of the relative angular position of the two adjoining coaxial ducts prior to application of the full clamping force.