The wheels are 4.5" in diameter and about 1 1/8" thick. There are two wheels included and they are modified to fit a splined servo shaft such as the Hitec standard servos. It includes 2 long screws for mounting the wheels on the servo shaft.
SparkFun's minimal design approach to Arduino. This is a 5V Arduino running the 16MHz bootloader.
Open Box - The MGS1600GY is a sensor capable of detecting and reporting the position of a magnetic field (typically magnetic tape on the floor) along its horizontal axis. with custom aluminum mounting bracket