The CPAP Battery Pack and ResMed S8 DC Converter will provide you with up to 24 hours of power for your ResMed S8 CPAP machine. If your traveling, camping, or just want some backup in case the power goes out, this small lightweight battery will be a perfect accessory to your CPAP therapy.The battery weighs only 2lbs. and will provide up to 24 hours of power with no humidification. Adding heated humidification will greatly reduce the amount of time the battery can power your machine. We recommend that you test your machine with the battery before going on a trip to gauge how long it will power your machine. When charging your cpap battery pack you must use the charger that comes with it. If you use any other charger for your travel battery pack you run the risk of damage to the battery and an increased risk of possible fire hazard. This combo comes with the DC adapter required to connect the CPAP Battery Pack to your ResMed S8. Important: This cable will not work with the ResMed S8 Compact or the ResMed C-Series Tango. Please Note: High Pressures, Humidifiers and Heated Tubing will significantly decrease the running time of the battery charge.