UEF testing approved for DOE;Only Center Flue manufactured with 2" high density foam insulation;R-Value (14) Closed cell UL 94 Approved;Brass nipple connection Diptube and Hot Water outlet *NEW*;Unique exposed couplings for leak detection *NEW*;Easy access to magnesium rod for replacement – 2 anode rod *NEW*;409 stainless steel baffle for greater heat conduction;Carlin Dual Aquastat 90000B10S1 designed for precise temperatures and safety features;Factory installed brass drawoff;Factory installed brass well for aquastat;Heavy duty glass lined steel tank – Cobalt Porcelain Enamel;Attractive baked enamel steel jacket;Made in the U.S.A.