Which aspect is NOT highlighted in Exley's principles for overhead diving?

The principle that is not highlighted in Exley's principles for overhead diving is the use of high-tech diving equipment. Exley's principles emphasize the importance of mental preparation, environmental awareness, and risk assessment as critical components of safe and effective overhead diving practices.

Mental preparation involves ensuring that divers are psychologically ready to face the challenges presented by cavern diving, which often requires advanced problem-solving and decision-making skills in complex environments. Environmental awareness emphasizes understanding the characteristics and potential hazards of the cave system, including water flow, visibility, and geological features, which can significantly influence a dive's safety and success. Risk assessment is fundamental to identifying and managing potential dangers associated with overhead environments, allowing divers to make informed choices and take necessary precautions.

While high-tech diving equipment may enhance a diver's experience and capabilities, it is not a core principle outlined by Exley. The focus is instead on the diver's education, mindset, and understanding of the environment, suggesting that preparation and awareness are more critical to safety than reliance on advanced technology.