Specifications:  Input voltage: 3V-35V.  Output voltage: 5V--45V.  Input curren: 5A (peak).  Product size: 72mm*48mm*16mm.     Instruction:  1. Access power supply (4.5-40V), the input indicator light, the module works normally.  2. Adjust the blue potentiometer knob (generally clockwise rotation boost, counterclockwise rotation step-down), and use the universal meter to monitor the output voltage to meet the need.  3. When the output voltage of the module can not be adjusted, always equal to the input voltage, please turn the potentiometer several times counterclockwise, and then use the module.     Using Attention:  1. This module is a boost module. The output voltage is greater than the input voltage.  2. The peak current output current is no more than 5A.  3. With voltage display, voltmeter error +/-0.1V, range 5-30V. (Note: when the input voltage is less than 4.5V, the board voltage does not work and does not display.).    Application:  1. Make a DIY stable power supply, input 12V, output can 12-35V adjustable, with voltmeter, display more intuitive.  2. Power supply for electronic equipment. You can set the output value according to your system voltage.  3. Make car power supply. Powering laptops, PAD, or digital products.  4. It can be used to make a DIY high-power notebook mobile power, configure a large capacity 12V lithium battery. Keep your laptop bright.  5. Used as solar panel voltage regulator.  6. It can be used to make a DIY high current moving current, and can be boosted to 5V with a single lithium battery. Ultra large current output with USB port and identification resistor and 2.5A. It can charge several mobile phones at the same time.     Package Included:  1 x Digital Step Up Power Supply Module DC-DC 3V-35V to 5V-45V