What should divers regularly check in their MK-20 system before a dive?

Regularly checking the integrity of the gas supply hose in the MK-20 system before a dive is essential for several reasons. The gas supply hose is a critical component that delivers breathable air from the surface to the diver. If there are any leaks, kinks, or damage in the hose, it could lead to a loss of air supply while underwater, posing significant risks to the diver's safety. Ensuring the hose is in good condition helps maintain a reliable breathing gas supply throughout the dive, allowing divers to focus on their task without the concern of running out of air or facing system failures.

While other components and conditions, such as the diving suit's visual appearance or the surface conditions, are also important aspects of pre-dive checks, they do not directly affect the immediate function of the breathing gas system like the integrity of the hose. Monitoring aquatic life activity, though essential for awareness, is not a mechanical check necessary for ensuring a successful dive operation with the equipment.