DCDC Converter, DROK Step Down Voltage Regulator Module DC 4.5-40V 36V 24V to 1.25-37V 12V 9V 5V 3V Variable Buck Converter Adjustable Electronic Power Supply Volt Reducer Transformer Stabilizer Board Non-isolated buck converter, dial down volt 36V 30V 24V to 12V 5V 3.7V 3.5V 3.3V 2V. Analog control, using a mini screwdriver to increase or decrease output voltage by adjusting the potentiometer, clockwise to step up voltage and counterclockwise to step down voltage. With over-temperature and short-circuit protection, hence it is safe to use. Wide Voltage input of 4.5-40V and output of 1.25-37V but has low power-consumption. Easy to make it work and convenient to accurately adjust the output voltage with a mini screwdriver.