Anaesthesia General 9e3f6e0b In infant (full term) diameter (mm) length (cm) of ETT used are – A 3.5,16 B 7,12 C 3.5,12 D 7, 10 High-Yield Explanation For full term infant, oral tracheal tube should have internal diameter of 3.5 mm and a length of 12 cm.