The ASP Link Battery Case allows flashlight users to safely carry spare CR123A Lithium Batteries. Batteries that are carried loose in a pocket or backpack can possibly contact metal objects and discharge or even cause excessive heat build-up. The ASP Link case securely carries a pair of CR123A batteries in a secure polymer case that protects the terminals from damage and keeps them from contacting anything. Additionally, the Link case can be connected to other link cases, allowing users to store several batteries and keep them from migrating to all corners of your pack!