Complex sentence: NGK Spark Plugs (U.S.A), Inc. produces products from two manufacturing locations: one location in Irvine California, which produces Spark Plugs; and another location In Sissonville, WV which produces both spark plugs and Oxygen Sensors.
Split into simpler sentences: NGK Spark Plugs (U.S.A), Inc. produces product from two manufacturing locations. One location in Irvine California with produces Spark Plugs and another location In Sissonville WV which produces both spark plugs and Oxygen Sensors.