Which feature helps reduce the amount of air needed to clear a mask underwater?

Which feature helps reduce the amount of air needed to clear a mask underwater?

• A. Soft silicone skirt.
• B. Low internal volume.
• C. Snug, comfortable fit.
• D. All of the above.

Answer: (B)

Mask clearing relies on replacing the water inside the mask with air. The amount of air you need to purge equals the air space inside the mask. A low internal volume means there is less air to fill, so you can push water out with less air, making clearing quicker and easier. A soft silicone skirt and a snug, comfortable fit help seal and prevent leaks, which aids clearing, but they don’t directly reduce the air required. So the feature that most reduces the amount of air needed is a mask with low internal volume.

Mask clearing relies on replacing the water inside the mask with air. The amount of air you need to purge equals the air space inside the mask. A low internal volume means there is less air to fill, so you can push water out with less air, making clearing quicker and easier. A soft silicone skirt and a snug, comfortable fit help seal and prevent leaks, which aids clearing, but they don’t directly reduce the air required. So the feature that most reduces the amount of air needed is a mask with low internal volume.