534 gallon glass lined R-16 insulated hot water tank, 125 psig.
ASME Section IV / HLW.
http://tankspecs.net/horizontal-watertanks-501-5000gall/WM737B.html

Manufactured in Los Angeles, CA 90021.
Roy E. Hanson Jr. Mfg. pressure vessel tank manufacturer.
http://hansontank.com
Tel: 213-747-7514