Elenco Precision Quad Power four linear regulated DC power supply unit, model XP-581. Features dual analog meters for voltage and amperage, fixed outputs (+5V, +12V, -12V), and a variable 2-20V DC output with front control knob and color-coded binding posts. Built with heavy-duty rear external heat sinks and dual 2N3055 power transistors, operating on standard 120V AC input. Suitable for electronics testing, hobbyist breadboarding, lab work, and circuit prototyping.