This shield lets you control a 16x2 Character LCD, up to 3 backlight pins AND 5 keypad pins using only the two I2C pins on the Arduino! The best part is you don't really lose those two pins either, since you can stick i2c-based sensors, RTCs, etc and have them share the I2C bus. This is a super slick way to add a display without all the wiring hassle. This shield is perfect for when you want to build a stand-alone project with its own user interface. The 4 directional buttons plus select button allows basic control without having to attach a bulky computer. The shield is designed for 'classic' Arduinos such as the Uno, Duemilanove, Diecimilla, etc. It uses the I2C pins at Analog 4 and Analog 5. It will also work perfectly with Arduino Mega R3's which have the extra SDA/SCL I2C pins broken out. Earlier Mega's have the I2C pins in a different location and will require you to solder two wires from the I2C pins on the shield and plug them into the different I2C locations at Digital 20 & 21. Note: This shield comes in kit form and requires assembly.