Cot PEHD Rainplus 40/88° Cot PEHD Rainplus 40/88° is a type of polyethylene high-density (PEHD) plastic that is designed for use in areas that experience a lot of rainfall. It is designed to be more resistant to water and moisture than traditional PEHD plastic. The 40/88° designation refers to the amount of pressure the plastic can withstand. This type of plastic is typically used for roofing, siding, window frames, and other applications where water resistance is important.