The Aquafax ECS Ventair Shut-Off Vent is designed to provide free air circulation in a range of weather conditions. The Shut-Off Vent is a waterproof version of the ECS Ventair/Ventilite ventilators which are designed specifically for marine use. In cases of excessive water flow over the decks, an inner sleeve complete with flush handle, can be closed by moving in an upward direction whist a downward motion returns the unit to standard operation.