This is a Black Plastic Storage Box Case Holder for Battery 2 X AA Cell Box, with DC Power Plug. The 5-inch cable is terminated with a standard 5.5 x 2.1mm, center positive barrel jack connector. The connector mates with the barrel jack on the Arduino (among a number of other products) allowing you to easily make your project battery powered.
Features :
1. Holds two AA batteries.
2. The standard 5.5 x 2.1mm barrel jack at the output.
3. Easy install, convenient to use.
4. High-quality plastic material.