In 1954, Amtrol invented the first expansion tank to control pressure build-up and energy consumption in heating and chilled water systems. More than 50 years later the EX is still the worlds leading expansion tank and is proudly made in the USA! The EX in-line boiler system expansion tank collects expanded water as system temperatures rise, reducing potentially dangerous pressure build-up. Equipped with a 100 percent tested sealed air cushion, water-tight reservoir, air stem for pre-charge adjustment, and a deep drawn steel tank, the EX is reliable and built to last. The EX-60 is ideal for residential applications. USA Made All EX thermal expansion tanks are made in the USA. Heavy Duty Tank From the deep drawn steel tank to the water-tight reservoir for expanded water, this thermal expansion tank is constructed for maximum strength and efficient energy consumption.