Just works. - Streamlight Stinger Flashlight Battery Stick

Not much to say here. Its a FACTORY battery and it works the way it was designed. Perfect backup power and second spare. I keep it charged and in the truck with the supplied cap in place. Past purchases of this type battery have lasted 6 years and counting. YMMV based on number of charge and discharge cycles. I fully discharge my batts normally once a week in normal usage 3-6 hours per night shift at the airport.