The RD-125B is a DC-DC converter manufactured by Mean Well. It is a non-isolated Type 2 topology, which means it provides power in a single output direction with no isolation barrier between the input and output voltages. The RD-125B is a 12V input, 5V output converter, with a 3A maximum output current. It is also compact in size, measuring only 2.47 x 2.1 x 0.95 inches. This is because it does not include any heat sinks or fans, making it ideal for applications where space is at a premium. Additionally, the RD-125B is equipped with adjustable output voltage, over voltage protection, overtemperature protection, and short circuit protection.