Check the listing for details. Bluetooth Music Tesla Coil Arc Plasma Loudspeaker Square Wave Music Spectrum. Condition: New. Listed at 55.24 USD. Better performance and visual effects: with circuit protection design, will not damage the input device, can play music in better quality than normal arc plasma loudspeaker. Specially design for square wave music to get incomparable sight experience. Strong function but easy use: with Bluetooth connnection, no grounding and audio cable needed. Designed with frequency knob, energy knob and mode switch, and euipped with neon bulbs, freely to adjust proper display effects you want. Endless fun and spark inspiration: with the function of wireless transmission and loudspeaker, can light gaseous tube and kind of bubbles. It is a perfect teaching tool to spark students’ interest of science, also a great gift. Mini size but powerful energy: only 4.17*4.17*2.36in, but it has a shocking energy. Its.