Features: - This is a great DC to DC step-up power supply module for electric equipment, digital products, etc. - Input and output are designed with screw terminals for convenient wire connection and disconnection. - There is a heat sink on board that would ensure a better heat dissipation. - Designed with USB and 2.5A large current output, can identify resistance and charge several phones at same time. - It can also be used as a power supply for laptops or voltage regulator for solar panels. Specifications: Input voltage: 4.5-40V. Output voltage: 5-45V. Input current: max 5A. Voltage Display Range: 5V-30V(if input voltage is lower than 4.5V, it will not display). Voltage Display Error: +/-0.1V. Size: 72 x 48 x 16mm. Instruction: 1. Connect the module to power supply (4.5-40V), the input indicator light is on, and module is working normally. 2. Adjust the blue potentiometer knob (generally turn clockwise to step up and turn counterclockwise to step down) and check the output voltage with a multimeter until it meets requirement. 3. If the output voltage of the module can not be adjusted, which means it is always equal to the input voltage, please turn the potentiometer counter-clockwise for several circles then the voltage can be adjusted normally. Note: 1. The output voltage is greater than the input voltage before it can be used 2. The current can not be greater than 5A . 3. The input voltage can not be less than 4.5V. 4. This kit requires professional knowledge and ability, please make sure you know how to use it. Package Included: 1 x Digital Step Up Power Supply Module