What safety equipment is essential for each EANx dive?

For each EANx (Enriched Air Nitrox) dive, having a secondary regulator and a surface marker buoy (SMB) is essential for safety. The secondary regulator serves as a backup air supply in case the primary regulator fails, ensuring that the diver has a means to safely ascend or, in an emergency, share air with a buddy. Reliability of equipment is critical in diving scenarios, especially when using enriched air, which can have different ascent procedures and considerations relating to gas management.

The surface marker buoy is also vital as it allows divers to signal their location to boats and support teams on the surface. This is especially important when diving in busy areas or where boat traffic is common, ensuring that the diver's position is visible and reducing the likelihood of accidental encounters with vessels.

While other options may include useful equipment for diving, they do not encompass the combination of safety measures that ensure both immediate air supply and surface signaling capability, which are crucial for mitigating risks associated with enriched air diving.