Abstract: A clamping collar for sealing by perimetrically connecting the axially aligned ends of two parts which are circular in external transverse cross-sectional shape. The collar includes a strip formed into an open loop, V-shaped in longitudinal section, having two circumferentially opposite ends, and a tightener for extending force on the ends for circumferentially tightening the collar on the ends of the two parts. The tightener includes a separator for separating the two ends when the collar is loosened, for facilitating the opening and removal of the collar from the parts.