The thru-hull uses a buttress style thread for exceptional strength and are not compatible with other valves. All valves have one part number for the complete assembly. Each valve is factory assembled and pressure tested. Forespar® cannot be responsible for valves disassembled and modified or reassembled improperly.
Marelon® is the modern material for marine plumbing systems. It's non-corrosive proprietary formulation of Polymer composite compounds uses resins and additives to produce a superior marine grade product that will not deteriorate like traditional bronze marine plumbing parts.