Spark plug

Spark plug with single-ground electrode.

Iridium tipped spark plug that is standard on the Honda VFR800

A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed fuels such as aerosol gasoline, ethanol, and liquefied petroleum gas by means of an electric spark.

There are many variants of spark plugs, designed to improve performance such as iridium tipped spark plugs and V-tipped spark plugs designed to increase the size of the spark for more reliable combustion.