Features . 50 gallon.. Natural gas ultra low nox water heater.. 40000 btu.. Draft diverter outlet size 3 in. With integrated adapter for 4 in. Vent option.. 0.60 energy factor.. Recovery at a 90 degrees rise-gallons hours 43.. First hour rating 91.. 1 in. Insulation factory installed t&p valve new advanced gas control system incorporates an internal microprocessor providing enhanced operating parameters a tighter differential for precise sensing faster heating response to optimize performance.. Valve is self powered uses a thermopile to generate the power needed to operate valve incorporates self diagnostics monitoring.. Dimension - 26 l x 23 w x 60.38 h in.. Item weight - 168 lbs.