The Bosch Spark Plug Kit - 140738 is a comprehensive set of products designed for servicing a car's spark plugs. It includes a variety of components that are essential for maintaining the proper functioning of a vehicle's spark plugs. The kit contains spark plugs, which are responsible for creating the spark that ignites the fuel in the engine. It also includes spark plug wires, which deliver the electrical current from the ignition coil to the spark plugs. Additionally, the kit contains a spark plug socket, which is used for removing and installing the spark plugs. The spark plug gapper, included in the kit, is used to ensure that the gap between the spark plug electrodes is correct. Lastly, the kit also includes dielectric grease, which is used to lubricate the spark plug wires and prevent corrosion. Overall, the Bosch Spark Plug Kit - 140738 is a convenient and essential product for maintaining the performance of a car's spark plugs.