Material: It consists of electronic accessories, surface nickel-plated (antioxidant), inner conductor: pure copper.It's durable and long-lasting for you. Package includes: 2 x step-up power modules.DC step-down module, which consists of a high-precision potentiometer (clockwise increase, counterclockwise movement down) Feature: High efficiency and low ripple with power display.In addition to current limiting and voltage regulation, step-down function.High reliability, strong vibration resistance, good electromechanical performance. A wide range of applications: This module can be used in the buck domain where the input voltage is higher than the output voltage, e.g.Maintain a stable output voltage and limit the output current over a range of input voltages.Used for booster voltage stabilizer power supply, DIY adjustable mobile power supply, booster charger. If you encounter any problems during use, please feel free to contact us