An elongated flexible tube structure is provided defining a plurality of individual passages extending longitudinally therethrough. The passages include an air vent passage, a suction passage and a fluid injection passage and the passages include first end portions opening separately outwardly of one end portion of the tube structure. The other end portion of the tube structure defines an outer tubular jacket enclosing and defining the second end portion of the air vent passage. The second end portion of the injection and suction passages are defined by separate tube sections disposed in and extending longitudinally of the tubular jacket. The end of the tubular jacket remote from the aforementioned one end portion thereof has the corresponding end of the suction tube section anchored therein and the latter includes lateral suction openings formed therein opening outwardly into the interior of the tubular jacket. The tubular jacket includes longitudinally spaced lateral air vent openings formed therein and the fluid passage tube section includes a flexible free end portion extending outwardly through one of the air vent openings. Also, a longitudinal midportion of the tube structure includes an outer inflatable bladder surrounding the tube structure and an inflation passage extending longitudinally of the tube structure having a first end opening into the interior of the bladder and a second end opening outwardly of the aforementioned one end of the tube.