9V to Barrel Jack Adapter
Cost: $2.95 each
Description: This simple cable has so many uses! Plug a 9V battery into one end and connect the other end to anything with a 5.5x2.1mm, center-positive barrel jack.
Use this cable to battery-power any device that needs 9V and has an on-board barrel jack - it works great for Arduinos, development boards, evaluation boards, and more!