Input + to Battery +, Input- to Battery-. Output + to load +, Output- to Load-. Never reverse the input polarity or it damages your fuses or converter. This one can’t be used in tele-communication, medical, aerospace and military. if you need these request, please give us message. DC 36V/48V Battery Vehicles and boats Output side only connects DC loads Notes: This converter can not be connected to solar panels or wind turbine directly. Wide input voltage from 30V to 60V Stable output voltage is 12V 100% actual photos 100% full rated power 100% full stable output Current 100% burn-in test High efficiency IP68 Waterproof Cooling by free air convection Over current protection, Over voltage protection Over temperature shutdown, Short circuit protection, Output reverse polarity protection Dimension: 2.91*2.91*1.22 inch Net Weight: 0.6 lb