The COVIDIEN Shiley Inner Cannula 4DIC is a sterile, latex-free disposable inner cannula that is intended for use with Shiley tracheostomy tubes with a 15 mm snap-lock connector. It is made from a soft, clear PVC material and features a smooth, rounded-tip obturator for easy insertion. The 4DIC also has a soft swivel flange for added comfort and stability.