The pencil coil gets its name from its slender, cylindrical shape, resembling a pencil. These coils are typically smaller and more compact than traditional ignition coils, making them easier to install in modern engine designs where space is limited. Pencil coils are often mounted directly on top of the spark plugs, eliminating the need for spark plug wires.

The rail type ignition coil is a component consisting of two or four ignition modules. The rail type coils simplify installation operations and reduce the amount of material required. If one ignition module is damaged, the entire guide rail needs to be replaced. The rail type coils are suitable for 3  to 16-cylinder in-line and V-type engines. It is mounted directly on the spark plug.

With the development of ignition technology, the distributorless ignition system is becoming more and more common. DIS coils are usually mounted directly on or near the spark plug without the need for a distributor. Each coil is responsible for providing a high voltage to a particular spark plug. The DIS system uses sensors to determine the precise time each cylinder generates a spark. 

A distributor is an electrical and mechanical device used in the older spark ignition engine ignition systems. The primary function of the distributor is to deliver electricity from the ignition coil to each spark plug at the right time.

A coil on plug (COP) ignition is a system where an individual ignition coil is placed atop a spark plug, found on the head of the cylinder and separating coils from exhaust heat. This makes it easier for spark plugs to receive voltage.