Product description NWANSI DC 36V/48V to DC 12V 5A-60A Buck Power Converter, Step Down Voltage Regulator Supply Module Product Wiring Instructions The red cable at the input end connects to the positive "+" terminal of the power supply. The black cable at the input end connects to the negative "-" terminal of the power supply. The yellow cable at the output end connects to the positive "+" terminal of the device. The black cable at the output end connects to the negative "-" terminal of the device.