The EM-300-16, Spark Plug Trainer, is designed to demonstrate how spark plugs work in automotive distributorless ignition systems. The spark plug plays an important role in ignition systems since it emits a spark for the explosion of the fuel/air mixture inside the internal combustion engine cylinders. The spark plug is quite simple in theory: It forces electricity to arc across a gap, just like a bolt of lightning. The electricity must be at a very high voltage in order to travel across the gap and create a good spark.

The EM-300-16 simulator allows students to adjust air pressure either by adding or removing oxygen inside the glass cylinder to simulate a combustion chamber, and to check the gap between the spark plug electrodes to produce the required fire.