... and slinky, the surface is smooth . 2)Japan Toshiba vacuum electron tube, powerful output, 1-10 ton air pressure, oil pressure ... and accurate. 3)American NL-5557 high sensitive sparkle protection tube and circuit ,automatically cuts off the high frequency, restrain ... Frequency 27.12MHZ Input power 15KVA Rectifier SILICON DIODE Oscillation tube 7T69RB Max pressure 10T/15T Gap between electrodes 200MM ...