Works with all makes & models of CPAP and BiLevel Machines, No prescription required, Available in three different sizes and capacities, Includes stylish soft side carrying case, AC Charger & DC Power Cord, LED power gauge on battery indicates remaining usage time. Battery Packs are equipped with standard smart charges that keep the battery topped off and ready to go as an emergency power backup during power outages. Battery Packs can also be used to power other devices that operate from a 12V DC Current such as portable DVD players, iPods, laptops, iPads, cell phones, and more. Perfect for camping! Outdoor enthusiasts can finally play hard and sleep soundly after a day of hunting, fishing or hiking. Great for tent campers and use in RVs and travel trailers. With the addition of the 150 or 225 watt sine wave inverter or a DC converter you can safely recharge your CPAP Battery Pack via the cigarette lighter socket of a vehicle - giving you even more time to enjoy your outdoor adventures!