The structure?consists of?a?black?wooden box.?Inside, there is a high-voltage electric circuit.?In the?front, there are 3 poles?for?gas - filled tube which includes Hydrogen (H2), neon (Ne), and mercury (Hg), there is also a pore to see the spark needle. At the back, there is an on/off button, the fuses is connected to the electrical?plug which can be connected to?220 V. AC 50 Hz.