MrPEX® Composite Multiport Tees are made from a blend of engineered high performance Polyphenylsulfone (PPSU) resin to achieve a long-term durable product. These PPSU fittings are durable, light weight, corrosion free, and resistant to chlorine and other substances that may be present in today’s potable water supply. The Sulfone resin has been used and refined over the past 20 years and has proven a very reliable replacement for brass and copper fittings. MrPEX® multiport tees meet ASTM F2159. MrPEX Stainless Steel Press Sleeves and PEX Press tools are required and purchased separately.