What unique feature is associated with the Spanish windlass technique?

The Spanish windlass technique is characterized by the use of a stick or rod to tighten a ligature, which can lead to asphyxiation or strangulation. This method typically involves wrapping a rope or cord around the neck of the victim, and then using a stick to twist the ligature tighter and tighter, thereby increasing the pressure around the neck. This unique feature of using a stick to apply leverage distinguishes the Spanish windlass technique from other methods of strangulation that might not employ such a tool.

In contrast, the other options describe methods or tools that do not align with the key aspects of the Spanish windlass technique. For example, a complex knot can be a part of various strangulation methods but does not specifically refer to the unique mechanism of leveraging a stick. Similarly, strangulation with bare hands does not utilize the device or mechanism that defines the Spanish windlass. Lastly, using a thick fabric strip for garroting refers to a different technique rather than the specific implementation of windlass mechanics.