This product is made of high-quality nylon designed to endure the use on salt water environment. The mirror polished 316 grade stainless steel trim cover provides better aesthetics after installation. The product is quick to install and involves no mounting and screws. Dimensions: Head diameter 1.89 inches; Thread diameter 1.31 inches; Hose diameter 3/4 inches; Hull thickness 1-3/4 inches; Total length excluding trim cover. Package includes one MARINE CITY 1.89 inches head diameter nylon thru-hull or through hull with 316 grade stainless steel trim cover for 3 by 4 inches hose on boats, yachts, marine vehicles.