Cast bronze. Flange is machined to fit hull and grooved to retain bedding compound. Neck is threaded to approximately 3/8" from flange. Includes flange nut. UL Listed.THRU-HULL CONNECTION (PERKO)SKU: 85226035968$61.99PriceQuantityAdd to CartFeaturesHose1"Flange2-3/16"Max Hull1-7/8"