This DC cord is compatible with the Philips Respironics DreamStation series (CPAP Pro, Auto CPAP, BiPAP). One end connects to the vehicle's cigarette lighter outlet with 12v DC, the other end connects to your CPAP directly. With this DC power cord, you won't need a regular AC charger.
Battery cable: if you won't have access to a cigarette lighter outlet, you can purchase the battery cable option which allows you to connect to the battery directly.
Humidifier: This 12v DC shielded DC charger is compatible with CPAP with a humidifier. However, using a humidifier will quickly drain your batteries. So unless your vehicle/camper/boat has a big battery capacity, we do not recommend you use a humidifier with your CPAP machine while camping or traveling.