The invention relates to an insertable plumbing element (1) that can be inserted, by means of a sleeve-shaped insertion plug (2), into an end-located insertion opening in a plumbing pipe section, which insertion plug (2) has, at least on the outer circumference, an outer layer (3) of elastic material for securing it by frictional engagement in the insertion opening. It is characteristic of the insertable element according to the invention that a reinforcing sleeve (4), which is composed of a material that is inflexible in comparison with the outer layer and which is surrounded by the outer layer (3), is provided to reinforce the outer layer (3) transversely to the plug longitudinal axis.