It has a nice standard 0.1"x0.1" prototying grid with big pads
Comes with Stacking headers and plain header, choose whichever you want when soldering together
A IC pattern for adding DIP ICs up to 20 pins
Power rails down the middle and sides
A reset button and an extra general use button
2 3mm general use LEDs, red and green, as well as 2 matching resistors
A pass-thru ICSP stacking header so you can stack any kind of shield on top, and/or use an AVR programmer
A surface-mount chip area for up to 14 SOIC size parts
Compatible with tiny breadboards
Every pin is brought out!
Gold plated pads
2 x 0.1uF capacitors on either side for extra power stability

Arduino UNO Prototype Shield is used in the cases where you want to build more applications without using any external Breadboard.The Prototyping Shield is designed to facilitate easy prototyping with an Arduino or an Arduino compatible board. It provides prototyping board space to build custom circuits and is great to build custom projects with the Arduino. All IO pins of the Arduino can be tapped into through header pins and empty solder pads for easy expansion.