The Arduino Proto Shield PCB (Printed Circuit Board) allows you to build your circuit on a mini breadboard and then transfer that circuit directly to pads on the PCB that exactly match the holes in the breadboard. This provides the double benefit of easing the design by using a breadboard and then quickly making that design robust by soldering the parts to the PCB. Pads next to the breadboard pads match the Arudino pins so that you can solder connections to your Arduino pins without interfering with the Arduino stacking headers. This kit works with the newest Arduino R3 headers and with the older boards. In addition to the PCB and mini breadboard, the kit contains a 10-pin, a 6-pin, and two 8-pin male/female stacking headers and a 4-pin female I2C header.