PE100 is a version of HDPE and stands for Poly Ethylene with an Minimum Required Strength (MRS) of 100 at 50 years and 20º according to ISO4427. It has an optimum balance of three key properties: Minimum Required Strength (MRS) – this provides long-term strength and creep resistance. Stress crack resistance (sometimes referred to as slow crack growth resistance). Rapid crack propagation resistance.