The Lionel Hobby Transformer Model 7H20 6-03-2923-000 is a ready-to-go pre-built power supply unit designed for model railroads and trains. With a power type of AC and a voltage of 120 V, this transformer is essential for providing the necessary power to your model train setup. Used primarily for accessories on your model layout. Made by the well-known brand Lionel this transformer is a reliable and efficient component for your hobbyist needs.