The basic spark plug has undergone a number of changes over recent years to accommodate the demanding operating conditions required by modern engines. Changes in Spark plugs have been caused by demands for longer life and also improved ignitability in today's lean burning modern engines.

It is critical that each cylinder fires to prevent unburnt fuel from reaching the catalytic converter and causing damage. With engine manufacturers striving to improve fuel consumption, the possibility of misfire becomes a problem.

It has been proven that a very thin electrode will improve ignitability, however a thin electrode made from nickel would quickly erode and fail, therefore NGK has necessarily turned to precious metals to withstand the harsh environment.

All vehicle manufacturers in India use only "Resistor" type spark plugs, as per Government of India EMI (Electro Magnetic Interference) regulations implemented in July 2003.

It is important to note that spark plugs are consumable with a limited service life and as such must be changed at regular intervals.