This is a DC-to-DC power converter that steps up voltage from its input connections to its output connections.  This device accepts input voltage from 2V to 24V DC.  It can output anywhere from 2V to 28V DC.  It can handle a maximum current of 2 Amps and delivers a maximum efficiency of 93%.  The built in potentiometer (pot) allows adjustment of the output voltage to the exact desired level.  The heart of this device is the MT3608 constant frequency, current mode step-up converter IC.  The MT3608 is a compact IC intended for small, low power applications.  The MT3608 features automatic shifting to pulse frequency modulation mode when under light loads.  The MT3608 includes under-voltage protection to prevent damage during an output overload.