Equalization is one of the most essential underwater skills to learn for Freedivers. We must equalize pressure in the middle ear to avoid pressure-related ear injury. If not equipped with equalization techniques, we would be too painful to continue diving down. The most pragmatic equalization technique is Frenzel equalization; however, I began with Valsalva maneuver, a forced expiration of air against a closed airway that leads to increasing pressure in ears.
FiDive to Be Free 