Features:

• Digital I/O Digital input/output terminal, a total of 0 ~ 13.
• Analog I/O Analog input/output terminal, a total of 0 ~ 5.
• Support the ISP download function.
• The input voltage: when connected to the computer USB without external power supply, external power supply 5 v ~ 12 v dc voltage input.
• Output voltage: 5 V dc voltage output and 3.3 V dc voltage output.
• Using Atmel Atmega328 microprocessor controller & ATMEGA16U2 usb driver thus no additional driver is required 
• Plug & play

Optional:

• Acrylic Base
• Breadboard 400-TP

Related links:

• Arduino Uno Home Page
• Getting Started
• Programming Reference
• Arduino Forum