Can be produce >50kv, dont go on the circuit's results.
It uses 4 Mosfets, 2 slighly coupled inductors and 2 capacitors. The inductors (transformer) oscillate with the capacitors at their respective resonance frequency. The mosfets helps in this as well as powers the circuit while breaking the electric current so fast to produce a high magnetic flux which supplies power to the two coupled tuned circuits.
This thus produces a high frequency AC current which when passed through a flyback transformer will produce AMAZING RESULTS!!!!!
Hope you like it.