Shiley Single Cannula Tracheostomy Tube, Low Pressure, Cuffed (#SCT) Size #10 measures: I.D. 10.0 mm, O.D. 13.3 mm and Length 105 mm. I.D. is the inside diameter of the cannula. O.D. is the distal outside diameter of the cannula (not including cuff features. Length is the distance from the neck plate to the distal tip of the tube at center-line.