Diving Helmet

Diving helmets are worn mainly by professional divers engaged in surface supplied diving, though many models can be adapted for use with SCUBA equipment.
The helmet seals the whole of the diver's face from the water, allows the diver to see, provides the diver with breathing gas, provides an anchor point on the diver for the umbilical supplying the breathing gas, protects the diver's head when doing heavy or dangerous work, and usually provides voice communications with the surface. If a helmeted diver goes unconscious but is still breathing, the helmet will remain in place and continue to deliver breathing gas until the diver can be rescued. In contrast, the SCUBA regulators typically used by recreational divers must be held in the mouth, and will usually fall out of an unconscious diver's mouth resulting in drowning.