Abstract: A tube connector (1) has a connecting member (2), a nut (7), and a tube (11). To connect the connecting member (2) to the tube (11), the tube includes a formation (12) with two formation portions (14, 16). The first formation portion (14) has a first tensioning face (13) which extends parallel to an end face (4) of the connecting member (2). The second formation portion (16) has a second tensioning face (15). The tensioning face (15) extends in such a way which corresponds to the second conical bore (9) of the nut (7). The end face (4) includes an annular groove to receive a seal (23). The seal (23) achieves a precision sealing effect. A connector (1) which includes a formation as described above provides advantageous sealing conditions and ensures that the formation cannot be overtightened, especially during repeat assembly procedures.