Blonde Girl With A Diving Mask In The Sea

• diving helmet - often worn by divers using surface supplied diving equipment.
• hard hat - part of the old fashioned standard diving dress.
• fluid filled mask - the need to equilibrate the internal pressure in the mask by exhaling air through the nose reduces the freediver capacity to dive deep. Masks or swimming goggles with high power lenses (40-200 diopters) have been developed in this view: they are filled with water or saline fluid.