Goobay 30575 is a voltage tester. It is a handheld device used to measure AC and DC voltages. It has a digital display, adjustable sensitivity, and a built-in LED light. It can measure voltages up to 400V, and it is ideal for testing power outlets, automotive circuits, and other electrical applications. It is a UL-certified device and includes a range of safety features, such as an automatically shut-off function to prevent overloads.