Bivona FlexTend TTS Plus Pediatric Straight Neck Flange Tracheostomy Tubes, Size 5.5. Sterile with obturator, twill tape and disconnection wedge. Portex Bivona FlexTend TTS tracheostomy tubes are designed for neonatal and pediatric patients who require intermittent or temporary cuff use. I.D. 5.5 mm x O.D. 8.0 mm x 114 mm overall length.