The Prototyping Shield makes it easy for you to design custom circuits. You can solder parts to the prototyping area to create your project, or use it with a small solderless breadboard (not included) to quickly test circuit ideas without having to solder. It's got extra connections for all of the Arduino I/O pins, and it's got space to mount through-hole and surface mount integrated circuits. It's a convenient way to make your custom circuit and Arduino into a single module.
Arduino Uno Proto Shield
1.0 Arduino Pinout 1 Reset Button 1 ICSP Connector 14 pin SMD footprint (50 mils pitch) 20 pin Through Hole footprint (100 mils pitch)