The LifeChoice Activox Sport off its internal battery alone will produce oxygen for up to 5.5 hours on a setting 1. Did you know that there is a way to actually make this already incredible unit even better? To further extend the overall operational time of the Activox Sport by up to 3 hours, all it takes is the addition of the LifeChoice external battery. The external battery will never be too much to carry around, as it weighs .75 pounds and is smaller than your smartphone at 3.5” x 3” x 1.75”. The addition of the external battery does not mean you have to carry it around—just simply attach the battery to its designated port on the unit and if you have the carrying case on, the battery easily slides into the side pocket for a secure fit. Not only will you extend your overall battery life, but when it comes time to charge, the external battery can be recharged by either the AC adapter or through a cigarette lighter outlet in most vehicles with the DC adapter. Charging is even accomplished while breathing. Extend the time you get to spend with family and friends by upgrading to the LifeChoice Activox Sport external battery.