Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net> Hi Greg, It is an RF filter and voltage limiter designed to protect NSTs. The following picture tells all: http://hot-streamer-dot-com/TeslaCoils/Misc/NSTFilt.jpg Cheers, Terry At 12:41 PM 10/4/2001 +1000, you wrote: >What is the terry filter? > >Greg Peters >Department of Earth Sciences, >University of Queensland > >Phone: 0402 841 677 > >