NTI Boilers Firetube Boiler 95% AFUE 10:1 Turndown, 199k-Input, 184k-Gross Output, 139.5 lbs, Water Content-2.8 gallons, 1-1/4" MPT Heating Connections, 3/4" MPT Gas Connection, 2" or 3" Vent Size, Dimensions-18-1/2"D x19-3/4"W x38-1/4"H