Kimdrox DC-DC 3-35V to 3-27V 5V/12V Voltage Converter Regulator Auto Power Supply Boost Buck Volt Board Module Properties: LM2577 non-isolated automatically step-down step up power supply module; Dimension: 48 x 23 x 13.5mm ( L x W x H ) Input voltage: DC 3-35V; Input current: 2A MAX Output voltage: 3-27V continuously adjustable. ( adjust potentiometer Clockwise boost voltage, adjust potentiometer Counterclockwise buck voltage) Input: IN+ Input Postive, IN- Input Negative; Output: OUT+ Output Postive, OUT- Output Negative Reverse polarity protection: NONE, please connect carefully.