Mufa PEHD Rainplus 32 PEHD Rainplus 32 is a high-density polyethylene (HDPE) rainwater pipe manufactured by Mufa. The pipe is made from a special blend of HDPE resins which provides superior strength and flexibility. It has a smooth inner wall, an outside diameter of 32mm, and is available in lengths ranging from 5m to 25m. The pipe is designed to withstand UV radiation, chemical attack, and temperature fluctuation. It is also resistant to corrosion and is considered to be 100% recyclable.