EPDM rubber is a synthetic elastomer which is formally known as Ethylene Propylene Diene Monomer. EPDM products are offered in a few variations. Their common feature though is that they are generally very good at resisting the degrading effects of weathering, ozone, and UV ray exposure. EPDM sheet rubber is highly recommended as a type of outdoor rubber for applications where there is significant environmental exposure. EPDM rubber is also highly resistant to extreme high and low temperatures making it the ideal rubber material for insulating heat and electricity.