Yeeco Numerical Control Voltage Regulator, DC to DC Buck Converter, Adjustable Step Down Voltage Converter Board, DC6-40V to 0-38V 8A Power Supply with LED Display & Heatsink Fan Integrated input MOS transistor reverse polarity protection circuit, no damage happens when connected reversely Adjustable DC to DC step down buck converter,6-40V to 0-38V 8A NC voltage regulator with LED display & heatsink fan IN+(Input +);IN-(Input -);OUT+(Output +);OUT-(Output -);Please check every mark on the module in detail before operation Button setting of step down buck converter: ON/OFF buttons for output voltage controlling; SET button for output voltage setting The numerical control step down converter's output current can reach 8A, please avoid short circuit when the power converter operates