<p>The fitting has a main body (3) with a central opening (1) and an outer sleeve (4) accommodating a pipe section (2). A space between the sleeve (4) and the pipe section (2) can be used for the insertion of a flexible pipe (6). A circular locking unit (7) provided with several elastic elements (10) is located inside the space and kept radial in position by a retaining element (8) also comprising elastic elements (19). When the pipe (6) is pushed into the fitting the teeth (10) of the circular element (7) are released and pressed against the pipe (6) while creating a sound indicating the appropriate positioning.</p>
