These are the core components, responsible for creating the spark that ignites the fuel. They consist of a metal shell, a central electrode, and a ceramic insulator. 

Connect the ignition coil or magneto to the spark plugs, delivering the high-voltage electricity needed for sparking. 

Spark plug sockets, gapping tools, or thread repair kits might be included to facilitate installation or address potential issues. 

These kits can help repair damaged spark plug threads in the cylinder head, restoring proper fit and function. 

Spark plugs wear out over time, leading to misfires and reduced engine performance. Replacing them with a kit ensures proper ignition and optimal power output. 

Kits provide all the necessary components for a complete spark plug service, simplifying the process for both professionals and DIY enthusiasts. 

Purchasing a kit can be more cost-effective than buying individual components.