Amtrol® Therm-X-Trol® Thermal Expansion Tank, Diaphragm Free Standing, Series: ST-C, 341 gal Tank Volume, 35 gal Acceptance Volume, 150 psig, ASME Yes/No: Yes, 24 in Dia, 57 in Height, Steel, 55 psig Pre-Pressure Rating, 200 deg F Maximum Temperature, FNPT, 1-1/4 in, Red Oxide Primer, Domestic