“24 hours” vent is completely automatic as it works with solar energy in sunny days and batteries, during night time. Forced ventilation is controlled through a dynamic impeller which turns clockwise to inflow and counter clockwise to exhaust air. The user adjusts the vent on the corresponding function through on/off switches. Active air movement absorbs moisture and refreshes the interior of your boat completely. Simultaneously, when water enters the vent special balls inside, it blocks its entry to achieve absolute impermeability. “24 hours” vents are made of white plastic. The vent 99689 is equipped with Inox plated cover.