The Turn Of The Century Electrotherapy Museum http://www.electrotherapymuseum.com White Snappy Sparks and Hot Ribbon Sparks 3" Pure white snappy sparks from a small Pancake Coil operated with .018 mfd 3600V 8mA (30 watts) The coil is only 7" OD and 1.5" thick. Hot ribbon sparks from a 10" Pancake Coil Mejla and Sumo