DROK Waterproof 24W Automatic Step Up/Down Regulator Stabilizer 8V-40V to 12V 2A Buck Boost Converter 12V 24V 36Vs Regulate Power Supply for Car Display Fans Solar Energy Uses synchronous rectification technique, has high conversion efficient to 93 percent ), Stable performance and low heat With input transient high Voltage protection, output over-current protection and chip over-temperature protection, safe to use Adopted the thermal conductive Silicone Glue technique, specially Made to be waterproof, anti-shock Easy to connect wires, input: red(+) black(-), output: Yellow(+) black(-); please connect wires correctly Wide application: car alarm, radio, interphone, motors, audio, Navigator, monitor, LED car display, air Conditioner, etc