These are some pictures of a couple of the coils I use for my demonstrations.

This coil has a 2.5" diameter secondary and produces about 12" of spark. This one is great for classrooms. 2inch
This coil has a 4" diameter secondary and produces about 3' of spark. This coil is suited for use in auditorium type settings. 4inch
This coil has a 9" diameter secondary. It is still under construction. It looks like it will be producing somewhere in the neighborhood of 7-8' of spark. Outdoor venues would be appropriate. 9inch
This is a special project coil that we recently built for a client Special Project

For more information, please feel free to contact me at mark.stolz at