Ethylene propylene rubber
Ethylene propylene rubber (EPR), (sometimes called Ethylene propylene monomer (EPM) referring to an ASTM standard) is a type of synthetic elastomer that is closely related to ethylene propylene diene monomer (EPDM rubber). Since introduction in the 1960s, annual production has increased to 870,000 metric tons.
Source: Wikipedia — Ethylene propylene rubber (CC BY-SA 4.0)