Check the listing for details. Spectrum Tube Power Supply. Condition: Used. Listed at 100.00 USD. The Spectrum Tube Power Supply is a high-quality educational toy designed for students studying science and nature. Produced by Eisco, a reputable brand in educational products, this power supply is essential for operating microscopes and conducting chemistry experiments. With its reliable and efficient performance, the Spectrum Tube Power Supply ensures a smooth and successful learning experience for students in the field of science and nature.