DROK LTC1781 100W DC/DC Step Up Converter 3-35V to 3-35V Switching Regulator Constant Current with Volt Ampere Meter USB Interface for DIY Mobile Power Supply This constant Voltage current boost module has high efficiency and little heat, low ripple and Stable performance With digital display, can show input Voltage), output Voltage) and output current) Output with USB interface and identification resistor, a single Lithium battery can be boosted to 5V to charge your phone Has over current protection and short circuit protection(input 15A fuse), safe to use Application: DIY a stabilized power supply, charge your electronic devices, stabilize Voltage for solar panel and etc