From Greg: Here is an explanation of how docs pro plugs work: "While the small vent allows equalization to occur it does not allow debris to enter and it prevents earwax from washing out which exposes delicate ear tissue. The Proplugs keep ears warm by storing the head’s conductive heat; the warmth provided by the plugs drastically reduces the risk of thermal shock. Due to surface tension the vented plug also reduces abrupt pressure changes from reaching the sensitive eardrum which contributes to easier eq...