Need a battery for your Arduino that is high enough to regulate the voltage to down to a solid 5V? Well here comes the 9V Snap to 2.1mm Barrel Plug Cable to your rescue! It allows you to plug in 9V and 7.2V rechargeable batteries to anything with a 2.1mm Barrel jack on it.
Give your project a muscular interface with the Compact Motor Driver Robot (CMDR) Shield! Bi-directionally drive TWO gear motors or a single stepper motor, read 6 analog sensors, and control up to 8 servos all at the same time.