Abstract: A method of manufacturing a composite annular seal for a semiconductor process chamber is provided. The method includes extruding a first elastomeric material in uncured form to form a cord of uncured first elastomeric material and extruding, via crosshead extrusion, a second elastomeric material in uncured form onto an outer surface of the cord of uncured first elastomeric material to form an uncured radially layered cord. The uncured radially layered cord includes an inner core of the first elastomeric material and an outer layer of the second elastomeric material. The second elastomeric material is different than the first elastomeric material. The method also includes co-curing the first and second elastomeric material of the uncured radially layered cord to form a cured radially layered cord. The method also includes splicing, via hot vulcanization, a first and second end of the cured radially layered cord to form the composite annular seal.