If you've ever tried to connect a 3.3V device to a 5V system, you know what a challenge it can be. The SparkFun bi-directional logic level converter is a small device that safely steps down 5V signals to 3.3V AND steps up 3.3V to 5V at the same time. This level converter also works with 2.8V and 1.8V devices. What really separates this Logic level converter from our previous versions is that you can successfully set your high and low voltages and step up and down between them safely on the same channel. Each level converter has the capability of converting 4 pins on the high side to 4 pins on the low side with two inputs and two outputs provided for each side. Description: The level converter is very easy to use. The board needs to be powered from the two voltages sources (high voltage and low voltage) that your system is using. High voltage (5V for example) to the 'HV' pin, low voltage (3.3V for example) to '', and ground from the system to the 'GND' pin Logic level shifter Bi-Directional with 4 channels between high logic and low logic Small module with 1.3cm X 1.5cm With 2 rows of 6 pin Compatible with breadboard, can be directly use in breadboard Usage: For example: High voltage is 5V, low voltage is 3.3V HV connect with 5V power supply connect with 3.3V power supply GND connect the power negative pole x input/output 3.3V TTL HVx input/output 5V TTL Bi-Directional transform between x and TVx Package Includes: 1 x Bi-Directional transform module 2 x rows of pins(9 Pack)