DENSO offers the GK4-7 Iridium Saver Spark Plug and rubber boot kit for Cummins ISX12 G & ISL-G engine applications. This protective rubber boot insulates the plug from the harsh engine environment. Combined with our reliable, long lasting Iridium Saver Spark Plug, DENSO is the perfect combination for Cummins natural gas engine applications. P N # 674-2002 ISL-G and L9N Part Number: 674-2002 Package Contents: 1 x Iridium 3-Prong Spark Plug (Part number: GK4-7#4) 1 x Spark Plug Boot (Part number: 674-1000) 1 x Dielectric Grease