The device (1) has an elongate flexible element (2) having two ends (4, 6), and a locking unit (8) circularly locking the flexible element in a predetermined diameter position. A tip (10) includes a reinforcing core (14) that is made up of rigid material, and an opening (18) is provided at one of the ends as part of the locking unit. The tip is inserted with the end of the flexible member into the opening at the other end for locking the locking unit. The tip is fixedly connected with the former end and separated after locking the flexible member by the locking unit. The elongate member consists of a small extent stretchable material. The reinforcing core comprises metal or hard plastic material. The device is made of a transparent or colored material i.e. medical grade silicone.
