Bronze thru-hull fittings offer long-term durability in the marine environment.Unlike the raised profile of mushroom head thru-hull fittings that can catch debris and cause drag, flush head thru-hull fittings reduce drag and fuel consumption. Bronze material offers excellent durability in the marine environment. Fittings include nut.SizeMax. Hull ThicknessFlange ODSFPLU#Model1/2"2 3/16"1 11/16"0331DP4PLB1132433/4"2 3/8"2"0331DP5PLB1132501"2 9/16"2 1/4"0331DP6PLB1132681 1/4"2 15/16"2 7/8"0331DP7PLB1132761 1/2"3 1/16"2 31/32"0331DP8PLB113284