These metal RO storage tanks are assembled using a virgin polypropylene liner, high-grade chlorobutyl diaphragm, and a patented stainless steel water connection. They have deep drawn steel domes and precision weld seams for reliability. Sealed brass air valves and O-ring sealed air valve caps ensure a leak-free air chamber. Finished is two-part epoxy primer and with the option of blue or white polyurethane paint.