Marathon® non-metallic electric water heaters are durable, lightweight, and warranted not to leak as long as you own your home. Seamless, blow-molded, polybutene tank impervious to rust and corrosion. Multiple layers of filament wound fiberglass give the tank unmatched strength. Polyurethane insulation helps reduce energy consumption. Recessed drain valve is out of the way brooms and scrubbers.