Package includes: 10 x MT3608 DC-DC step up power apply module Specifications: Maximum output current: 2A Input voltage: 2V-24V Maximum output voltage: 28V Efficiency: 93% in maximum (Minimum) (input-output) difference voltage when input is at (2 V and 50% of max-input-V), loading at (50% and full rated current). Method of use: The adjustment of potentiometer can adjust output voltage, output voltage is greater than the input voltage. Attention: The input voltage should not exceed the maximum input voltage. The peak current output current no more than 2A. Tips: Reverse the potentiometer 20 times before taking the goods to test. Some customers report that the output voltage of the module cannot be adjusted and is always equal to the input voltage. When you encounter this kind of problem, please turn the potentiometer counterclockwise for more than 10 turns, and then use the module to adjust the voltage normally.