Mallinckrodt Medical Inc Shiley™ Low Pressure Cuffed Fenestrated Tracheostomy Tube 8 Size 81mm L, 7-3/5mm I.D. x 12-1/5mm 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.