Adafruit Industries3216

This kit gives you everything you need to build the shell of a 2-wheel-drive Mobile Platform Robot! You get the metal plates that make up the chassis, two DC drive motors with matching wheels, and a caster ball for balance. You'll fill in the rest with a power supply, microcontroller board, and motor controller. The differential drive (two separately driven wheels) allows for a near zero turning radius while the high-strength aluminum alloy body plus high-quality high-speed motors make it suitable for flat indoor surfaces. Also it's adorably small!

 Kit includes: 

• 2x Drive Motors (drive with 3-6VDC, 200-400 mA run, 1.5A hard stall)
• 2x Wheels
• 1x Plastic Caster Ball
• Anodized aluminum frame and all mounting hardware for assembly

Assembled Dimensions:

• Length of Metal Plates: 100mm/3.9"
• Width of Car (wheels assembled): 109mm/4.3"
• Height (wheels assembled): 60mm/2.4"