The product is a lot of 9 Martek Military Grade DC/DC converters, including models PSD-278, PSD-277, and PSD-371. These converters are designed for use in demanding industrial and military applications, offering reliable and high-quality power conversion capabilities. With the trusted brand of Martek behind them, these converters are sure to meet the needs of testing, measurement, and inspection tasks, providing stable and precise power supply for various equipment and instruments. Ideal for professionals seeking precision and durability in their power supply solutions.