A collar for applying a radial compressive force to an outer surface of a tube and a tube assembly including the collar and the tube.

For stabilizing a pipe connection, in which a first pipe (10) is inserted into a second pipe (12) that has an insertion funnel (20), a stabilizer element (22) has a clamping ring (24) with several tensioners (48) distributed over its circumference, which in the final assembly position engage in an intermediate space between the first pipe (10) and the insertion funnel (20), and tense the first pipe (10) and the second pipe (12) against each other. The clamping ring (24) is composed of several mutually connectable ring segments, in particular of two half shells (34).