A Glow Plug is a heating device used to aid the starting of diesel engines. In cold weather, high speed diesel engines can be difficult to start because the mass of the cylinder block and cylinder head absorb the heat of compression, preventing ignition. Choosing high quality plugs is essential. NGK Glow Plugs (U.S.A.), Inc. is the largest OE supplier and manufacturer of glow plugs, oxygen sensors and A/F sensors for domestic and import vehicles in North America. With over 80 years of automotive expertise, NGK’s family of automotive products are driven by extreme dedication to innovation, performance, and quality. For decades, NGK application engineers in Wixom, Michigan and Fond du Lac, Wisconsin have collaborated with auto manufacturers to provide technologies fit for the vehicles of the future. NGK Spark Plugs (U.S.A.), Inc is committed to be the premier partner to customers, while maintaining strong standards for durability and operational performance in every product.