This module features the MT3608 2Amp step up (boost) converter which can take input voltages as low as 2V and step up the output to as high as 28V. The MT3608 features, automatic shifting to pulse frequency modulation mode at light loads. It includes under-voltage lockout, current limiting, and thermal overload protection.
This module has a multi-turn trimpot (potentiometer) that you can use to adjust the output voltage. Since the trimpot has 25 turns of adjustment you can easily adjust the output of the module to exact voltage you need.
Boost converters are a great way to easily increase a given voltage, but that boost comes at the cost of less output current compared to input current.
Since this is a boost converter,  the output voltage has to be higher than the supplied input voltage.
 
                      Specifications
Input Voltage
2 to 24 V
Max Output Voltage
28 V
Max Output Current
2 A
Adjustment
25-Turn Trimpot
Efficiency
up to 93%
Switching Frequency
1.2 MHz