EPDM (also referred to as ethylene propylene diene monomer) is a 45 mil or 60 mil geomembrane made with a high quality synthetic rubber compound that allows the geomembrane liner to lay flat in a wide range of temperatures for up to 20 years or more in fully exposed weather conditions. The flexibility of the liner conforms well to irrgularities in the subgrade and makes it an ideal geomembrane for a variety of applications. EPDM is available in a 45 mil or 60 mil thicknesses.