This is a Black Plastic Storage Box Case Holder for Battery 4 X AA Cell Box, with DC Power Plug. The 5-inch cable is terminated with a standard 5.5×2.1mm, 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. The case box can keep your batteries organized and protected. The holder case is designed with leads for easy to solder and connect. This battery holder case is perfect for the devices need a 6V external battery. Note: the average voltage regulator has about 1V of dropout (but can vary greatly). This pack, with normal alkaline batteries, will output ~5.5V causing a normal 5V board to run at around 4 to 4.5V. This depends on a lot of what board and processor you are using with the battery pack.
