About this item 4PCS AC/DC to DC Buck Step Down Converter Module 3V 3.3V 5V 6V 9V 12V 15V 24V DC 5V-50V Adjustable Step-Down 3A Power Supply Adjustable AC/DC to DC buck converter power supply module Voltage Regulator Input AC voltage range: AC 5V~AC30V or DC 5V-50V. Due to the large fluctuation of AC voltage, the recommended AC voltage range has been reserved. The power module uses a high voltage design, with a maximum input voltage of 50V (limited by filter capacitor voltage) and can withstand high current operation with an external radiator. Input voltage range: AC 5V-30V, DC 5V-50V Output range: DC 3.3V-33V Size: 4.65 x 3.27 x 1.3 inches