Mallinckrodt Medical Inc Shiley™ Low Pressure Cuffed Fenestrated Tracheostomy Tube 4 Size 65mm L, 5mm I.D. x 9-2/5mm O.D. Shiley™ Fenestrated Cuffed Tracheostomy Tubes (FEN) allows for weaning patientFrom tube by facilitating upper airway breathing. Fenestrated inner cannula aids in weaning and speaking.