DROK LTC1871 3.5V-30V DC Boost Converter Power Transformer Voltage Regulator 5V/12V Step Up Volt Module Power Supply Board for Car Auto Motor Motorcycle Automotive It is a DC boost converter with Voltmeter; display input and output Voltage alternately With mos tube for reverse connection circuit protection and will NOT burn when being connected reversely Has a red LED indicator; freely definable power-on statue; press the button behind Voltmeter to open or close the Item Simple wiring connection: in+: positive input/in-: negative input/out+: positive output/out-: negative output With good mounting holes and double terminals, Voltage can be adjusted by Turning the small screw on the potentiometer