Uponor PEX-a provides flexible, durable, reliable and consistent piping systems that offer corrosion resistance, kink repairability and a 25-year transferable limited warranty. With Uponor AquaPEX for plumbing in sizes up to 3" and Wirsbo hePEX oxygen-barrier pipe for radiant and hydronic distribution in sizes up to 4", there’s an Uponor PEX-a solution available to meet most any residential or commercial application, the company states.