HDPE (H = High, D = Density, P = Poly. E = Ethylene)

HDPE is considered to be preferable to common PVC for outdoor durability. Under a microscope PVC reveals a perfect octagon pattern making it brittle. When PVC is pressured with temperature changes it is apt to shatter like glass. On the other hand, HDPE vinyl resembles a massive spider web making it more elastic. When under pressure, HDPE 'remembers' its original form and returns. It will virtually never crack and is ideal for long term outdoor vinyl use.