Cowl Vents are available in both low profile and standard height contours. These vents are a perfect air intake supplement to solar ventilation, and are also commonly used as a bilge ventilating system with or without a mechanical blower. Marinco was the first supplier of soft, durable PVC vents that are flexible and safe. For interchangeability, Marinco 4" cowl vent models fit into the same 4" Snap-In deck plates used by the Combo and 12V vents (3" or 4" sizes).