**Core Concept**
An armoured endotracheal tube is a type of endotracheal tube designed to provide extra support and protection during intubation, especially in patients requiring prolonged ventilation or those with difficult airways. The tube's unique features include a metal wire coil embedded in the wall of the tube shaft, which enhances its rigidity and resistance to kinking.

**Why the Correct Answer is Right**
Option B is incorrect because armoured endotracheal tubes do not have a radiopaque line like normal endotracheal tubes. Instead, the metal wire coil embedded in the wall of the tube shaft serves as the radiopaque marker, allowing for easier visualization on radiographs. This design feature is crucial for confirming the correct placement of the tube.

**Why Each Wrong Option is Incorrect**
**Option A:** This statement is true, as armoured endotracheal tubes indeed have a metal wire coil embedded in the wall of the tube shaft, which provides additional support and resistance to kinking.

**Option C:** This statement is also true, as the metal wire coil embedded in the wall of the tube shaft makes the armoured endotracheal tube more resistant to bending and kinking, making it easier to handle and manipulate during intubation.

**Option D:** This statement is true, as armoured endotracheal tubes typically have a slightly thicker outer wall compared to normal endotracheal tubes, which allows for the incorporation of the metal wire coil.

**Clinical Pearl / High-Yield Fact**
When selecting an armoured endotracheal tube, it's essential to consider the patient's specific needs and the type of procedure being performed. Armoured endotracheal tubes are particularly useful in patients with difficult airways or those requiring prolonged ventilation.

**✓ Correct Answer: B. It has radiopaque line like normal ETT**