A semi-crystalline, very low diene-containing ethylene-propylene-diene terpolymer (EPDM) and has a low viscosity for excellent processing characteristics and low unsaturation for stability during long term exposures to heat and ultraviolet (UV) light. It is designed for extrusion and molding processes in low and medium extension compounds and can be peroxide cured. In addition, this polymer can be used for modification of thermoplastic materials such as polyethylene or polypropylene.