Sea-Dog Sea Dog Mushroom Vent With Plastic Cover 8in. Fully adjustable with a manual knob. Translucent center provides additional light down below. O-ring and gasket prevent water ingress. Trim piece provided for thru deck installations. 4 hole required. Constructed of injection molded nylon. Includes all necessary hardware for installation. Features of Sea-Dog Sea Dog Mushroom Vent With Plastic Cover Provides passive ventilation for your cabin by reducing stagnant air Protects against mold and mildew without needing to open a hatch Fully adjustable with a manual knob Translucent center provides additional light down below O-ring and gasket prevent water ingress Package Contents: Sea-Dog Sea Dog Mushroom Vent With Plastic Cover Sea-Dog 727525-3: Sea Dog Mushroom Vent With Plastic Cover 8in