This is a simple 4 cell AA battery holder. The 5-inch cable is terminated with a standard 5.5×2.1mm, centre 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.
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. Please consult yer datasheet.
Other types of casing are also available on our website with delivery to any city of Pakistan. Visit our website for updated price and pictures.