The MB102 is a breadboard power supply module manufactured by the YwRobot Corporation i. It provides dual 5 V and 3.3 V power rails, and has a multi-purpose female USB socket.
A very simple breadboard power supply kit that takes power from a DC wall power supply and outputs a selectable 5V or 3.3V regulated voltage.
The .1″ headers are mounted on the bottom of the PCB for simple insertion into a breadboard. Pins labeled VCC and GND plug directly into the power lines. The lone pair of pins have no electrical connection but help support the PCB.
There are two pins available within the barrel jack footprint. Any stripped +/- DC supply can be connected instead of the barrel connector. Board has both an On/Off switch and a voltage select switch (3.3V/5V).