This GPIO Cable bridges your Pi with other PCB or breadboard so that you can use those Pi pins easily. It fits Pi's GPIO (general purpose input/output) which contains 26 sockets perfectly. You can send and receive high/low, 3v/5v and I2C/SPI data using the pins.     Also recommend you the T-Cobbler Breakout for Raspberry Pi and Basic Bread Board to breakout the Pi pins.