This is the newest sensor/expansion shield for the Arduino Uno, version 5.0.  This expansion module sits right on top of your Arduino Uno and makes it incredibly easy to add sensors and other components to your project.  This board extends the digital and analog interfaces of the Arduino Uno, in addition to the IIC interface, SPI, Parallel and Serial LCD, A/D converter, bluetooth, etc.  It adds a reset button and extra power headers.