These compact power bus boards allow you to neatly and efficiently direct electrical power to multiple low voltage, low current sources, such as LED lights, small motors etc. without the need to solder a single power wire pair to a large awkward bundled wire knot. You can gang several boards together as you like. The board makes it easier to solder resistors into the circuit as well, so you don't have to fumble with trying to insulate and solder the resistors to the component lead wires.

There is also a spot for soldering in a Shottky diode (not included) for "idiot proofing" polarity, to protect the components from accidental pole reversing. If you don't want to use the diode, you can just put a jumper wire across the "D1" terminals.

Two mounting holes are also in the corners (indicated by large white squares) if you want to use screws to mount the boards to your project.

You can also daisy-chain or stack them, allowing you to add more units for more components.

In the first example here, which is based on a 2 cell, 3 volt power supply (the minimum needed to light 3V LEDs), the Shottky diode (covered later) is not needed as it also has resistance and is replaced with a wire jumper. Also, the LEDs will withstand a reverse bias of just 3 volts, so if you want to use a 3 volt power supply to use with LEDs, the following type of setup is viable.
Note that if you are using 3 volt LED's exclusively, and they are all exactly the same type from the same batch, you can bypass the resistors with wire jumpers like the diode bypass. Nevertheless, a 1 ohm resistor is recommended for stability.

Below is a typical setup for lighting some LEDs with a 12 volt power supply. In this case, the Shottky diode is recommended as it will protect the LEDs from possible damage if the power supply is accidentally hooked up backwards.

It is very important to note that LEDs and the Shottky diode are polarity sensitive, so you must make sure you install them correctly.