Battery - Battery life is determined by the number of cells in it. For example, a 8 cell battery will last longer than a 6 cell battery. A battery is either a primary or a secondary battery. In some laptops, primary and secondary batteries are interchangeable. If they are not, you will need to know the battery type to make the right choice. There are also some special types of batteries known as Reserve/CMOS batteries that maintain your computer’s internal settings. Please use the System Drill Down or the Service Tag look up feature for buying a battery. This will allow us to identify physically compatible batteries for your PC. Power Supply -Typically, power supplies are a direct replacement for the original part. Please use the Service Tag Lookup feature in the Parts For Your Dell tool. This will allow us to identify your PC’s power limits and chassis requirements and make recommendations. There are some power supply units called redundant power supplies that can be removed without shutting down the computer. Redundancy is available only for some servers. Adapters - For adapters, you can use either the System Drill Down or the Service Tag look up functionality. This will allow us to identify the voltage limits and physical compatibility requirements of your system. Please note that some of our replacement products are provided as kits or assemblies. These kits may contain additional parts required for installation; these parts will be listed separately as 'Component Parts' in the Highlights section of this page. In case a product is not sold as a kit or assembly, it may require complementary parts for ease of installation. Please note that this replacement product is refurbished. Dell provides a warranty of 90 days on all refurbished products. For more information about warranties, please click here: www.dell.com/warranty . Device Type: Power supply Power Capacity: 250 Watt Pricing Type: Refurbished Manufacturer Warranty: 90 days warranty Device Type: Power supply Power Capacity: 250 Watt Pricing Type: Refurbished Service & Support: Limited warranty - 90 days